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Topic Review (Newest First)
11-29-2015 05:15 PM
actmobmar Just got done putting 600 miles on the gto in 4 days, for the Daytona turkey run, didn't skip a beat. Oil pressure hot 2500 rpm is 70 psi, hot idle 25, but in the dead of summer in 95 degrees it will go to 10 to 15 psi hot idle. Carb is a holley 750 dp, but I'm going to try another carb
11-29-2015 05:11 PM
actmobmar crower solid pn 60310, duration at .050 is 240 int, 248 exh, lift .477/.501) power is from 2800 to 6k rpm
11-28-2015 07:40 AM
Mr. P-Body It's been a LONG time... Which cam? Crower stuff is pretty dated.

You still have some white elephant parts there... RPM is not the intake of choice. We like Torker 2 for street builds. You may need 800-plus CFM to take advantage of the porting (who did it, what pattern?).

36 degrees is a tad too much for a factory head. We limit them to 34 "total".

Oil pressure indicates "loose" bearing clearances. As long as it ALWAYS makes at least 15 (hot idle, "in gear"), and relieves at 60-70, you're good. It can be a little unsettling.

Jim
11-25-2015 05:35 PM
actmobmar Just wanted to give an update, I've been slacking off,sorry! Car is up and running, in prime though! I ended up buying rods and pistons from butler, I ported the heads, used the same crower cam, degreed and installed straight up, 9.2:1 compression, performer rpm intake, I did the oil restricted lifter bore oil feed mod (pita drilling and tapping all the oil feed holes!), holley 750 dp and edelbrock pump, headers and 2.5" exhaust. Car runs great, no blowby and doesn't burn a drop of oil. I feel that the oil pressure could be better, I did plastiguage it on Assy and everything checks ok per the book, but hot idle is 15 psi after a hi way drive, goes rite to 70 at 1200 rpm. Timing is set at 36 total, 16 base, using a pertronix flamethrower distributor. Performance isn't all that great though, in first gear at wot from 2500 it won't spin the tires, I guess just the way it is,but disappointed. Has a 12 bolt with 3.73 gears. Thanks guys, I think I need to work on it again to try and get more performance
03-08-2013 12:06 PM
Mr. P-Body Pontiac stroker "kits" cost in the $1,800 range, plus balancing. Add the forging and it goes up to about $2,200. About the same cost as the BBC and BBD kits, for about the same performance increases. You only need a forging if you're going to make more than 800 HP or rev it past 7,000. We "make up" our own kits for use with small chamber heads, using Icon pistons with an enlarged "dish". Same price...

I don't disagree about using the "numbers" block. 400s are still plentiful, and a "big car" code has no serious value. For the most part, the code is the ONLY difference between 400 blocks of a given year. The "988" block, '71-'75 is the most common and most popular.

FWIW

Jim
03-08-2013 08:52 AM
h0trod
Quote:
Originally Posted by actmobmar View Post
as far as your unmachined crank on the kit you put together, when you buy a normal kit i would assume everything is ready for assembly other then possibly balancing the whole thing? if that is the case it sounds like by the time you are done buying rings and bearings and having it machined you'll be at almost 2k$ plus?
pretty much. so if you got the coin, spend it on a complete kit, less headaches.

however, i would not use the stock block.
the only reason i say that, is because thats a high dollar car,
always nice when the #'s matching is a virgin.
03-08-2013 05:16 AM
actmobmar super nice people at butler and very knowledgeable! i'll buy the head gaskets from butler and be done w/ that part of it. i'm still waiting on a couple of price quotes for the stroker kit. as far as your unmachined crank on the kit you put together, when you buy a normal kit i would assume everything is ready for assembly other then possibly balancing the whole thing? if that is the case it sounds like by the time you are done buying rings and bearings and having it machined you'll be at almost 2k$ plus?
03-07-2013 12:02 PM
cobalt327
Quote:
Originally Posted by actmobmar View Post
i talked to butler yesterday and was advised against using the felpro gaskets, said the pattern was all wrong for the pontiacs, and he described it to a t. he offers his own line of gaskets w/ the correct pattern, but the victor may be a good way to go as well. i'm finding out the stroker kit will be around 2k for this engine, not the 1300-1500 advertised price, apparently i need custom dished psitons because of the head volume.
A big X3 on the crew at Butler. Highly qualified and I've never felt like they were trying to "sell" me on anything I didn't actually need- they answer questions/state the facts and the rest is basically up to you.
03-07-2013 09:10 AM
69 widetrack
Quote:
Originally Posted by h0trod View Post
the Butler boys, hands down, are some of the most awesome and helpfull folk ive ever had the pleasure of dealing with.

if you really want a stroker kit, you can buy it piece by piece.
i have not completed my engine yet. however i have purchased a
Eagle 4.25" stroke rough machined for the pontiac 400.
6.800 Eagle forged H beams.
i went to butler to purchase my ross pistons (good gawd at the .030 clearence between the wrist pin and the oil ring)
ive spent around 1400 dollars so far however i do not have bearings and rings.
im a budget builder, so i had to do it this way. also the eagle crank is unfinished, so a reputable pontiac engine builder is a must.

the only part of ths post that i didnt like, in my unprofessional opinion, was the demon carburator! they make great oil lamps, but i wouldt use one on any of my yacks!
455 blocks are great for towing, but stick to the 400 if you ar going for power.

HEI distributors??? i dont trust those ICM's but the HEI makes a great shell for a MSD 6 AL
I agree with much of what you say...especially the competence of the Butler boys. It does sound like your on a great Pontiac build and I was informed recently that they don't make Demon Carb's anymore...I'm a big fan of the Pontiac engines, I've had a few, even a 326 in the mid 70's that ran fairly strong. The 326 had a Holley 650 Carb and every Spring I'd get to replace the rotted out gaskets...I don't know if they've improved them over the years or if it was because the car was parked all Winter but my last Pontiac build was a 428, 30 over, ported heads, decent cam, balanced and Torker intake etc. ...running an 850 Demon. It ran like a champ...that was a few years ago and still haven't had to touch the inside of the Carb...maybe I got lucky...I don't know, but I was happy happy with the Demon.

Ray
03-07-2013 08:48 AM
h0trod the Butler boys, hands down, are some of the most awesome and helpfull folk ive ever had the pleasure of dealing with.

if you really want a stroker kit, you can buy it piece by piece.
i have not completed my engine yet. however i have purchased a
Eagle 4.25" stroke rough machined for the pontiac 400.
6.800 Eagle forged H beams.
i went to butler to purchase my ross pistons (good gawd at the .030 clearence between the wrist pin and the oil ring)
ive spent around 1400 dollars so far however i do not have bearings and rings.
im a budget builder, so i had to do it this way. also the eagle crank is unfinished, so a reputable pontiac engine builder is a must.

the only part of ths post that i didnt like, in my unprofessional opinion, was the demon carburator! they make great oil lamps, but i wouldt use one on any of my yacks!
455 blocks are great for towing, but stick to the 400 if you ar going for power.

HEI distributors??? i dont trust those ICM's but the HEI makes a great shell for a MSD 6 AL
03-07-2013 06:25 AM
69 widetrack Those guy's at Butler are fantastic...From the first time I spoke to one of the guy's, it was obvious that they knew their Pontiac's to a T. Anytime I've called they had the answer to any question I've ever had. Things might cost a bit more (machining etc) but I trust them and their judgement and that's worth the extra cost to me.

Did I say it right Uncle Dave...LOL.

Ray
03-07-2013 05:56 AM
actmobmar i talked to butler yesterday and was advised against using the felpro gaskets, said the pattern was all wrong for the pontiacs, and he described it to a t. he offers his own line of gaskets w/ the correct pattern, but the victor may be a good way to go as well. i'm finding out the stroker kit will be around 2k for this engine, not the 1300-1500 advertised price, apparently i need custom dished psitons because of the head volume.
03-06-2013 07:31 AM
Mr. P-Body Any "stock replacement" head gasket has the appropriate "reliefs" for the chamfers. We prefer the Victor/Reinz, but of course, Felpro is very popular. Unless static compression is over 12:1, there is no need for "special" head gaskets. Stock ones hold up fine. Just be certain you use the correct octane rating for the compression you have. You will have better service and good parts available at your local parts outlet. No need for "mail order". Pontiac parts are NOT rare. If they don't have them "on the shelf", they can get them in one day, as ALL the "big" warehouses stock them.

The chamfer in the block is to "unshroud" the intake valve. 396 and 351C also use the technique. The small loss of compression is far offset by the improved flow. In olden times, we would actually sleeve all the cylinders to rid them of the chamfer (for a "class" race car). Today, we make it a little wider... Due to the necessity of lower compression ratios for street engines in recent years, we've learned "flow trumps compression".

The 1/4" between the cylinders is no big deal. The aftermarket blocks, with their 4.350-4.4" bores, have nothing more to "leave", yet seal fine under "race" conditions. While it's true, the Pontiac has "only" ten head bolts, consider that those ten are 1/2", not 7/16", and they're located in the best possible locations. Note the center bolt on the lower row is "closer" to the middle of the block than the "outer" bolts. This is where the clamping force is necessary, and also what makes the Pontiac different from other engines using ten head bolts.

FWIW

Jim
03-06-2013 05:17 AM
actmobmar my engine has those. if you look close at the pic of the head the fire ring from the head gasket is barely touching the head between cylinders, and the ring is actually partially in the combustion chamber. why couldn't i go with a head gasket with a slightly larger bore size, as i would think it would make the rings larger in diameter and move it away from the edge of the chamber? here are some examples of felpro head gaskets PONTIAC 6.6L/400 Head Gaskets - SummitRacing.com
03-05-2013 04:10 PM
cobalt327 You want about 0.030" between the chamber and fire ring. ATM I do not have a single Pontiac head to compare to your 0.256" measurement. Hard to judge by the photo. The photo shows a lot of oil is reaching the chambers, though.

On the chamfer, I should have said notches (arrows below), not the small taper right at the top of the bores to help the pistons and rings to fit. The notches I was asking about are there to help flow. If that's also what you meant, disregard this.

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