# Pontiac main journals



## PontiacPaul (Dec 22, 2014)

I have been looking a a few local core engines to go through. I found a 455 and a 428. long ago i read that the 3.25 mains have oil supply issues at high rpms. Trend today is to use a 400 block and install the 455 rotating assy. with cut down mains. The 400 blocks around are nothing special but both of the core engines im looking at are 4 bolt blocks. I can't afford new aftermarket so im looking for a weigh in on the main issues from you guys.I have a top end from a motor build by ( the pontiac dude in fla.)I have worked 5c-8 100cc heads with alot of port and polish work matched to intake along with alot of high quality misc parts. These parts came from a 400 block with the 455 internals. It turned out to be a matching letter block for a 71 gto so the guy bought the engine for the block and i aquired most of the rest along with a tko 600. i'm inclined to get one of the 4 bolt blocks but need more info please weigh in. this is going to be a drag racing engine to get my feet wet again after alot of years away from the sport.thanks


----------



## geeteeohguy (Feb 2, 2008)

Your info is sort of correct: the 3.25 mains do have oiling issues ON the bearing, not to the bearing. Not as efficient due to the size of the bearing, as an oil wedge tends to build up. These engines don't like extended high rpm because of this. If the car is a low rpm cruiser, not an issue. The trend to use a 400 block and a 455 rotating assembly with cut down mains was 20 years ago, or more. Today, the trend is to use a 400 block and a custom crankshaft of your choice, all the way to 4.5" stroke or more. The most common is the 400 based 461". 400 blocks are stronger than the 421-428-455 blocks, 4 bolt mains or not. There is simply more metal in the crankshaft support areas...the 'hole' is smaller. So, my choice would be a stroked 400 block over a 421-428-455 all else being equal. But, if I were in your shoes and had hands on a 4-bolt 455 or 428, I would have no issues snapping either or both of them up for a build. An _excellent_ starting point. And the cubes are already there........


----------



## PontiacJim (Dec 29, 2012)

The 428 is usually the preferred choice. It gives you the smaller bore of the 400CI and .25" more on the stroke. You get the higher RPM's of the 400 and the extra torque the 428 puts out. Many were bored out to make a 440CI combo. These engines, with good heads & matched parts, will put you into the 10's in the quarter, or even better.

455CI is good, but limited by their RPM's. You can still build a good 10 second engine as above, but you have to build it with reduced RPM's in mind.

I would imagine that a 400CI block with 428CI engine kit from Butler would be a good choice as well. Currently $1898 for the rotating assembly. Forged crank is more.


----------



## PontiacPaul (Dec 22, 2014)

Ok so I will go 400 block. There is a nos 77 block avail locally for 800 still in the crate. If we eliminate hi buck ramair blocks, are there certain blocks better than others? There is a new3" 461 rotating assy. around from a failed project that never got going. 90 mile drive. I tried to called pontiac dude to ask about the heads i got someone one the phone that suggested to me that their stickers could have been put on a junk yard engine. no help there. When i stripped the engine apart it had the best of everything. forged pistons h beam rods studded block crank wiper high buck timing chain moly push rods comp cams hyd. harland sharp rockers extensive port work. it also had a modded holley 800 on it which i also have. No one i talk to knows of them other than to see crap talk on the web. I have everything except block and crank. I would have to think high 500s on torque but cant say for sure without talking to the builder. The last time I dynoed an engine was 20 years ago i dont even know if the guy is still around he was old then.


----------



## BearGFR (Aug 25, 2008)

Sounds like a nice piece! I've got a 461 in my car that I built out of the original, numbers-matching block. It has many of the same pieces you listed. I'm running a "medium" solid roller cam, mildly worked 72cc Edelbrock round port heads, "cleaned up" Torker 1 intake underneath a real 455SD Qjet. The car has gone 11.86 at the track. 

It put out these dyno numbers during break-in BEFORE I added the E-heads, Torker, and the fuel curve was way off.

http://www.garrettfamily.us/gto/docs/BestDyno.pdf

Bear


----------



## PontiacPaul (Dec 22, 2014)

What kind of improvement did the heads give you?


----------



## geeteeohguy (Feb 2, 2008)

Stay away from that 1977 block. The '75 and up blocks are known by the inner circle as the '557' blocks. They are cheapened up with much less web thickness and much less strength than the earlier blocks. The nickel content is lower, and the macnining/casting can be pretty sub-par compared to the '60's stuff. The BEST 400 blocks are '67-'72. They are the strong ones.


----------



## BearGFR (Aug 25, 2008)

PontiacPaul said:


> What kind of improvement did the heads give you?


I don't know for sure because I haven't had it dyno'ed since, but my SWAG at it is somewhere in the neighborhood of 30-40 HP. The new heads are gorgeous...










































































...and oh... "stock" E-heads come with 2.11 intake valves and 1.66 exhaust valves. Dave at CVMS fitted mine with 2.190 intakes and 1.77 exhausts. Scroll back also and notice how he unshrouded the valves where they come near the edges of the chambers. This is what you get when you deal with a craftsman who really knows what he's doing...










Bear


----------

