We do not have the information and tips arranged in any particular order, so you will have to search. The Charts for Bearing Clearances and for Torque Specifications are at the bottom of this page


Adjustable pushrods help in many ways. Basically, they allow the proper setting of lifter preload (distance lifter plunger is pushed down when lifter is on base circle of cam). This is especially important if the block and/or heads have been milled significantly – say .025" or more total. We recommend a lifter preload of .030". Adjustable pushrods may be used even if the heads and/or block have not been milled.


Rocker Arms p26.JPG (131472 bytes)

Are they worth it? A question often asked! For most street application, no. For most strip/street applications --- maybe! Certainly such cams as the SP 235 do not really require Roller Rockers since the lift on these cams is such that stock rocker arms hold up quite nicely.

           As a rule of thumb, with a lift of over .510" (using 1.55 rocker ratio), we recommend a good roller rocker assembly.

However, Roller rockers do give a greater efficiency with less resistance, more lift through a higher rocker arm ratio and just plain more dependability. You might find them to be like an investment - that is they would be a "one-time" purchase, since breakage would be nil.

They become a necessity with cams of .510" lift or more, however, since greater lifts tend to place more stress on the stock rocker arms, thus vastly decreasing the dependability factor.

There are 3 styles of Stock Rocker Assemblies:

Rocker Arm Assemblies p27.JPG (153400 bytes)Bottom: Used on '67-69 400 & 430, and 350.

Can be used on 455's using the 455 oiling system. Have 1.60 rocker ratio whereas others have 1.55 ratio. This style arm cannot be used on '70 later shafts.

Middle: Used on '70 and some '71 455's and 350's. Sometimes referred to as 'bathtub" style. Generally not as durable as the others. These arms came in Rights and Lefts

Top: Used on '71 up 455 and 350. '70 and up rocker assemblies can be used on 400, 430 and pre '70 350 heads as long as the engine is using the 455 and '70 or later oiling procedure. (Generally referred to as stamped steel. This is the style we sell. We have the 400, 430 style arms and the 'bathtub" style '70 arms available. Same pricing as the units we sell. 350 assemblies were same. Turbo V6 engines use the "stamped steel" type arms.

Bearing Clearances!

Proper bearing clearances have a lot to do with oil pressure. With proper clearances and a good Timing Chain Cover, a Hi-Volume oil pump is not necessary.

We recommend .002" clearance on all rod and main bearings, except for the rear main. Here we recommend .0025".

Grooved Cam Bearings: Generally, we do not recommend grooved cam bearings. The reason? When a bearing is grooved on the backside, bearing material is taken away, naturally. This somewhat weakens the bearing. Remember, the downward forces of the cam exerts most of the "wear" pressure on the bottom of the bearing. This is where the full strength of the bearing is needed.

INSTEAD of grooved cam bearings, we recommend running a small groove (at least 1/8" x 1/8") in the block, from the entrance hole on the passenger side, up around to the exit hole on the driver side. Then install the cam bearing so that no hole is at the entrance hole in the block. One of the two holes in the cam bearing should be in the 2 to 3 o'clock position so that oil will travel around the groove in the block behind the bearing and enter the cam journal area at the 2 to 3 o'clock position. This way, the oil goes directly downward, because of the rotation of the cam, to the area where it is most needed. If ever a problem occurs from wear (other than incorrectly installed cam bearings), this is the area it will show first. Good quality bearings are important. Race only bearings are not necessarily the answer as they are intended for a different use than Street and Street/Strip engines.

Adjusting Pushrods & Roller Rockers

Many of get frightened away at the thought of having to adjust pushrods. While its not exactly the most exciting thing to do, it is important. The process for adjusting push rods and roller rockers is the same.

We know from experience that .020" - .030" of preload on each lifter is desired. Very much more than this can result in the lifter plunger actually bottoming out on the bottom of the lifter. Too little preload results in plunger hitting the top retaining ring which can result in damage there. You do have some leeway with preload, but too much or not enough preload!

If your block and/or heads have been milled more than .020" combined (or you're not sure how much), then it is highly recommended you use adjustable push rods.

I'm sure you would like to know exactly how!

1) Before adjusting each pushrod, make sure its lifter is on the base circle or base of the cam lobe. This is very easy to determine if the intake is off the engine. If it isn't - then watch the movement of the valve as you rotate the crank. When the valve first begins to open, you want to stop and back off, maybe 1/4 turn of the crank. Remember, when the lifter starts rising on the lobe of the cam, it begins to push it upwards which in turn pushes up on the pushrod, rocker arm, etc. So, if you back off some, then naturally the lifter will be on the base of the lobe (or base circle).

2) Make sure the lock nut is loose.

3) Tighten the pushrod until you first feel it tighten firmly against the rocker arm. (If your intake is off, then look at the lifter [plunger, when it first starts to be push downward -- Stop).

4) At this point, turn the adjusting nut 3/4 of a turn more. This will give you approximately .030" preload on your lifter.

5) Tighten the lock nut against the adjusting nut.

6) Repeat process with nest push rod.

7) Time Saving Shortcut - For any given lifter which is resting on the base of the lobe, there will be more. Hence, you can actually do several before having to turn the engine.

In step 4 above, we mentioned that 3/4 turn represented approximately .030" preload on the lifter. This is usually the case. We say usually, simply because if the slop or slant of the threads of your pushrods are different, then 3/4 turn may be more or less than .030" preload. We have not seen any pushrods like this, but you should be aware of this remote possibility. The pushrods we sell and those on the market as far as we know are all the same thread.

Adjusting Roller Rockers -- Follow the same procedure.



Composite VS Steel

We often get the question, which seals best - composition or steel head gaskets. Our experience has been that both seal equally well with street engines. We feel the block and head (sealing surfaces) preparation play an important part in sealing. This becomes more critical naturally, with higher compression engines.

One of the advantages of the steel shim head gaskets is that of extra compression, approximately .25 gain. For example, if you now have a true 10:1 compression, then with the steel head gaskets, you would have 10.25:1. This is an inexpensive way to pick up compression, however, if you are rebuilding , then consider milling the heads and/or block a little extra and use the Fel Pro composition gaskets since they are considerably less expensive.

If you've been having sealing problems, then we recommend using Fel Pro "Blue" composition head gaskets or the new "Orange" head gaskets TA Performance has available. Both are really good. If you're wanting that extra compression from the steel head gaskets, then your next alternative is to check the "trueness" of the heads.


                                   Uncompressed                    Compressed

                         on sealing ridges                on sealing ridges

455 Steel                 .048 - .052"                          .020 - .022"

455 Fel Pro                  .050"                                     .038"

350 Fel Pro                 .052"                                      .039"


Soft composition intake gaskets can help sealing the intake to your heads, especially where you may have misalignment problems due to heads being milled. These will help solve your problem where the steel intake gaskets may not.

These are available in various sizes: Standard thickness is .062". Also available in .032" and .015" for 400-455. Contact TA Performance.

To the left, top, you will see how the steel valley pan has been trimmed to fit in the valley between the heads. This will help keep the hot oil off the intake. The steel section you see is "wedged" under the lower lip of the head on each head. The soft intake gasket is then positioned appropriately (bottom left).

.030" Over Blocks are Reusable!

Sometimes a .030" block will have minimal wear and can be reused with the same or new pistons with minor re-honing.

If the above is not possible, then consider using Lightweight Pistons with .038" overbore. This way you can use Chrysler Rings, RNG455PM .043 (our Part #)

Ring Thickness

All Buick pistons, rather they be cast, forged or hypereutectic, use the 5/64" rings. 1/16" rings are usually used with special made aftermarket pistons. They are mainly intended for race applications where every effort is being made to minimize friction. Generally, 1/16" rings are not recommended for street applications.

Timing Chain Alignment/Cam Timing Tip:

On any timing set, double roller or otherwise, just because you install the timing set with the dots lined up, does not mean the cam timing will be correct. It IS possible the dots may not be located correctly on the timing gears. If they aren't, then cam timing will be off. The only way to really know is to degree everything with a Degree Kit. Yes it's extra work, but that is the only way to really know!

Oil Pump Booster Plate – Get One!

We highly recommend the use of the booster plate. It helps pressure and oil volume while at the same time no placing excessive pressure on the distributor gear. It is not a hi-volume pump. Basically, it helps improve the oil flow patterns within the pump which in itself helps increase the flow and pressure.

We really do not recommend using Hi-Volume oil pumps, UNLESS adequate pressure just cannot be obtained otherwise. Hi-Volume pumps exert unnecessary pressure on both the distributor gear and cam gear. This pressure can "wipe out" a cam in as little as a few hundred miles. Use the Hi-Volume pump only as a "patch" when nothing else can be done and rebuilding the engine is not feasible. With proper bearing clearances, you should not need anything more than a Booster Plate.

Fuel Pump Arm VS Double Roller Timing Chain

With the installation of a Double Roller, it is highly advisable to watch for contact of the fuel pump arm with the chain. This can cause drastic problems quickly.

We recommend this safe procedure. Elongate the mounting holes in the Fuel Pump. Elongate them 1/8" inch on the right side of each hole (holding the pump facing you). This will allow you to install the pump 1/8" further away from the chain. Don't go any further than 1/8" as this will place the position of the pump arm on the cam lobe, too far outward, causing it to ride too far off the edge of the cam lobe which can present problems later on.


With the 400-455, keep in mind the year of the pulleys being used, since many of us often change pulleys. If in doubt – the short shaft pumps were generally used with the 400, 430, and '70 455's. Otherwise, most likely the long shaft pumps will be used. The short shaft pump measures 2" from the gasket mounting surface to the front end of the pump housing (not the end of the shaft). The long shaft pump measures 3" between these points.

We also highly recommend NOT using a rebuilt pump. You will be ahead of the game spending a little extra money to get a new one. We have been using and selling TRW pumps. Most local parts places can get them if they have direct access to Federal Mogul. Check around for best price as some parts houses do not have direct access and will have to charge more. Short Shaft TRW Part # is FP1400 and Long Shaft TRW Part # is FP1457.

Torque Tech Recommended Bearing Clearances:

The following recommendations are given in the Buick Manual. Our recommendations for Street/Strip Competition rebuilds are given under those. All-out race applications may or may not be the same.
  400-455    350
Connecting Rod Side Clearance   .0005-.0012" .0006-.0014"

Street/Strip Competition Buildup               w/Steel Rods
.0012-.0030"  .0012-.0030"
Connecting Rod Bearing Clearance .0005-.0012"  .0006-.0014"

Street/Strip Competition Buildup
  .0105-.0012"   .0006-.0014"

Crankshaft End Play @ Thrust Bearing
  .0003-.0023"     .0003-.0009"

Street/Strip Competition Buildup
.0005-.00075"    .0005-.00075"
Main Bearing Clearance   .0007-.0018" .0004-.0015"

Street/Strip Competition Buildup
  .0018-.0022"   .0018-.0022"
Rear Main   .0025"   .0025"

Cam Bearing Clearance in #1 Bearing
  .0005-.0025    .0005-.0025"

In remaining Cam Bearings
.0005-.0035"   .0005-.0035"
Intake Valve Clearance in Guide   .0015-.0025"   .0015-.0025"

Street/Strip Competition Buildup
  .001-.0015"   .001-.0015"
Exhaust Valve Clearance in Guide .0015-.0032"   .0015-.0032"

Street/Strip Competition Buildup
  .0015-.0020"      .0015-.0032"

Piston to Cylinder Wall Street/Strip Competition Buildup w/Forged Pistons
.002" - .003"  .002" - .003"

Street/Strip Competition Buildup w/Alum. Lt. Wts.
See Mfg. Recommendation

Street/Strip Competition Buildup  w/Fed. Mogul
.0015" - .0020"  .0015" - .0020"
Piston to Valve clearance (Intake) All Street/Strip .0080"
Piston to Valve clearance (Exhaust)  All Street/Strip .0080" - .0100"
Hydraulic Lifter Preload All Street/Strip .0030"
Valve Spring to Valve Stem Guide  All Street/Strip .0060"
Cam to Timing Cover All Street/Strip .0002" - .0004"


Torque Tech Recommended Torque Specs
                                                          400-455      350
Spark Plugs                                           15            15
Crankshaft Bearing Caps to Cyl Block     110           100
Connecting Rods                                    45            40
Cyl Head to Cyl Block                           100             80
Harmonic Balancer to Crank                   200          120
Fan Driving Pulley to Harmonic Bal           23            23
Flywheel to Crank (Auto. & Man.)             58            60
Fuel Pump Eccentric to Cam (350)                          50
Oil Pan to Cyl Block                               14           14
Oil Pan Drain Plug                                  30           30
Oil Pump Cover to Timing Chain Cover     10            10
Oil Pump Press Regulator Retainer                  35                    35
Oil Screen Housing (Pickup tube) to Cyl Block   8             8
Oil Pan Baffle to Cyl Block                     13            11
Oil Gallery Plugs                                   25             25
Oil Pressure Switch to Cyl Block             23            23
Filter Assem to Pump Cover                   20             20
Timing Chain Cover to Block                   29            29
  Timing Chain Sprocket to Cam             25            25
Water Pump Cover to Timing Cover          7              7
Fan Driven Pulley                                   20             20
Thermostat housing to Intake Manifold     20             20
Automatic Choke Cover to Intk manifold    8              8
Intake manifold to Cyl Head                    55            55
Intake Manifold (Aluminum) to Cyl Head   35            35
Exhaust Manifold to Cyl Head                20           20
Headers to Cyl Head                             35           35
Carburetor to Intake Manifold                 13            13
Fuel Pump to Cyl Block                        20            20
Motor Mount to Cyl Block                      60           60
Timing Chain Sprocket to Cam              22           22
Rocker Arm Cover to Cyl Head               4             4
Rocker Arm Shaft to Cyl Head               30            30
Delcotron Bracket to Cyl Head              35           35

Delcotron Adjusting Bracket to Cyl Head        22          22
Delcotron Mounting Bracket Thru Delcotron
         to Cylinder Head at Pivot Location       20            20
Starting Motor to Block                        35          35
Starting Motor Brace to Block               11          11
Starting Motor Brace to Starting Motor   11          11
Distributor Hold-down Clamp                13           13
Automatic Lower Flywheel Housing Plate        5            5
Flywheel Housing to Cylinder Block       35         35      


400-455 COMBUSTION CHAMBERS by Gary Bohannon


Heads have small combustion chambers for the best compression of Buick big block heads. Install Stage 1 valves only if 455 block is used due to valve shrouding by smaller cylinders (61cc).


Heads have good compression (65cc, 3.95 cu. In.) Several have told me '70 and '71 heads were the same. I have seen numerous sets and they are different. The '70 combustion chamber protrudes out around and between the valves. Look close and you'll see ('67-'69, also).


Heads have slightly less compression than all the older heads. The combustion chamber is receded beyond the 30 degree area of the seat leaving a partial lip around each seat. (71cc, 4.33 cu. in.).


Heads have open chambers (round) and very low compression (78cc, 4.73 cu. in.).

If 400-430 heads are to be installed on a 455 block, be sure to plug the oil passage located beside the upper front head bolt hole on the dip stick side of the block. If left open, serious oil leakage will result when 455 rocker shafts are used. Bet to plug with 1/8" pipe plug (female inverted hex head) or simply pound some lead into the hole.

Before purchasing any "junk yard" heads, consider that many engines in junk yards have been overheated. Agree on a guarantee and have them checked immediately for cracks.

Which Heads on Which Blocks!

Earlier heads will fit on later blocks. Never go the other way of using later heads on earlier blocks. You will usually always have a water jacket leak as water passageways do not line up.

1/8 Mile ET to ¼ Mile ET Conversion Hint!

      Here is a formula which works fairly well.  It ain’t perfect, but  good for comparison.

    ¼ Mile ET = 1/8 Mile ET X 1.56


1/8 Mile ET = ¼ Mile ET divided by 1.56

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This site has many tips, charts, and tech info that you will find helpful with your Buick Powerplant.  Please feel free to submit any tech info, etc. which we might consider adding to this page.
One of the Little Things that Adds Up to Horsepower….Insist on it!


The one factor which we have mentioned many times over is that of quality machine work on your engine, both block and heads. This cannot be emphasized enough! Its extremely important, so much so that it is well worth it to pay the extra to go out-of-town, if necessary, to get it done. It is even a good idea to go to someone who "really knows" the Buick engine and has a proven reputation with the Buick engine. If you live in the Central Florida area, then an excellent source is Scotty Guadagno at Scotty's Performance Engines (727-857-0001).  Be sure to ask for Scotty.  You've seen what Scotty can do with his 8 second Regal and his 3800 lb. '69 GS with our dyno engine in it.  Give him a Ring.  Scotty has the complete facilities to do anything you might need, from Stage 1 head conversions to building complete street or race engines.

But regardless,  Quality machine work is a must!  It's one of the little details which make a difference.  I hear of so many instances where individuals get their engine from the machinist, install it, then discover something is wrong and have to start all over.

Buick Big Block Casting Numbers -- Here is a link to a site where they're listed.  (Heads, Block, Intake)
Degree Your Cam: A part of the installation of any cam, should be the Degreeing Process.  Always Degree In the cam. Don't rely on just lining up the marks on the timing chain set.  This is NOT degreeing in the cam.  Any cam installation which does not include the degreeing process, is an installation which is relying on Lady Luck.  Lady Luck in that you are assuming the marks on the timing set are correct and that the cam was ground correctly.  Although it is the intention of every manufacturer to make their products correctly, it doesn't always happen for various reasons.  If you're going to the time, trouble and expense to improve the performance of your vehicle, then leaving the final step up to Lady Luck, just doesn't make sense!

We have seen timing sets be off as much as 8°.  In fact we once had a customer degree his cam and determine it was off 6°.  He was very upset and returned the cam saying it was junk.  Well we degreed it ourselves and the cam was correct.  So, he either degreed it incorrectly OR his timing set was the culprit.  But either way, if he had just lined up the marks on the timing set, then he would have had no idea why his GS was not performing very well.  He would have been forced to go through a process of elimination with carburetion, ignition and any other factors which might be a possibility for his problem, whereas this could have been eliminated with a little extra time degreeing the cam and making the necessary corrections.  This is where the Brute Timing set can be really handy.
Push Rod Oiling

By "Push rod oiling" we mean that the path of lubrication to the heads is through the holes in the top of the lifter, up through the hole in the push rod to the rocker arm.  Stock '67-69 350's, 400 and 430's do not oil through the push rods, but can be converted to push rod oiling by using '70 and later lifters and push rods.  The original oil passageway on '67 - 69 engines will need to "plugged" at some point, either in the block or in the rocker arm mounting tower in the head.

To block off or plug the oil passageway, use some soft metal like copper, brass or lead and force it into the openings in the rocker arm mounting tower.
Variable Duration Lifters

Hi-Vac or Variable Duration lifters such as Crane Hi-Intensities or Rhoades are variable duration lifters.  By this we mean that at low RPM they will bleed-off oil so they do not pump up totally, thus allowing your engine to idle more smoothly than it would otherwise.  They in effect reduce the lift of the cam at low RM.  As the RPM increase, so does the amount of oil retained in each lifter, thus increasing the effective lift of your cam to its actual amount.  These type lifters will increase low-end torque which is generally good unless this extra torque aggravates traction.  They will probably help if you have a low compression engine, but do not use them thinking they are a substitute for high compression. They are not!  They will probably help somewhat only on the low end. These type lifters tend to be somewhat noisy.
400-455 Push Rod & Rocker Arm Assembly Selection

Pre '70 engines oiled the heads up through the block to the heads, whereas '70 and later oiled up through the push rods and lifters. Oiling systems on Pre '70 engines can be converted to '70 and later simply by:

   1) Changing Lifter (must have oiling hole on top in them)

   2) Blocking off oil passage – easiest place is in the rocker assembly mounting towers – using some soft metal such as brass or lead.

   3) Changing push rods to '70 and later style with oiling through them.

   4) Changing rocker assembly to '70 and later is not necessary!  In fact, the '67-69 Rocker Assemblies are preferred sometimes since they have a 1.60 ratio ('70 and later rocker arms have a 1.55 ratio)– check out their condition before using.


We strongly recommend that with any aftermarket cam, chrome moly push rods be used. They are stronger than stock units and will vastly reduce flexing, which is common with higher lift aftermarket cams.

Buick GS Tech Info
Rick Martinez
Here is a web site with many really good hints too.
Buick Performance Club    Click Here.