Pontiac 400 Rebuild......Worth it?

[engine_ear]

It has been a while since I have driven my car due to the birth of another kid.....so now its time to stop ignoring my first child....my '70 Pontiac lemans sport:

I am thinking of pulling the tired 400 Pontiac block and doing a complete overhaul of the engine:


Should I put forth the effort of rebuilding the motor, or look at other options: crate motor, LS swap, etc.?
If I pursue a rebuild of the Pontiac 400 block, what are some engine 'blueprint' recommendations to get me moving in the right direction? How much money would I really save by doing any possible wrench-turning on my own?


Here is where my car currently stands:



Original 400 block
Original TH400 Trans
3.42 gears, 8.5 10 bolt rear end, posi.
Original heads (1.96/1.66) for 2BBl application
Edelbrock 750 cfm carb
Edelbrock performer intake


I would hope for a 400-450 hp, daily driver.
From my reading, it sounds like I should expect ~$6k for a complete engine rebuild, doing any possible wrenching myself?

Let me know your thoughts!

[Tim john---]

Based on your location I would highly reccomend you contact SD Performance, one of the top Pontiac performance people out there. Dave will treat you right on reccomendations to hit your goals and intentions. Super knowledgable, very honest and will not reccomend something that will not meet your expectations. If you want mid west sources there are several more Pontiac people I trust, Butler Performance out of Leoma Tennessee, BES (Tony Bischoff), Cliff Ruggles (Mt. Vernon, Ohio) "Cliff's High Performance. All these people are highly educated Pontiac builders and you can not go wrong with any of them.

Tim john---

[CampbellshotrodsAZ]

I talked it over quite a bit, different combinations, improvements, etc to make to my 455 in my 71 Firebird. I've decided that instead of spending time to hunt different cranks/blocks, etc to make say a 440 (higher revving), and trying to find a machine shop to build it properly, and risking longevity, I'm just going to pony up next year for a Butler 461 short block for under $5k, but it'll be built by one of the, if not the best Pontiac people in the USA, and feature the parts they know will work. I figure hunting down a 400 block, and the other parts would cost me near $3k for a local machine shop build, if not more, than I'm rolling the dice as to whether they know what they're doing. I'd rather pay a little more and get the Butler name. Pretty much bolt on some Edelbrock or Kaufmann heads, and be done with it.

The LS is definitely an awesome engine, I'm a believer. But at least in my case, building my Firebird with anything but a Pontiac engine is not an option.

[Skip Fix]

Get a 4.25 stroke crank/rotating assembly to make it a little bigger than a 455 and it drops in your block. Edelbrock or Kaufman D port aluminum heads , or Edelbrock round port heads. Pistons depends on if you use 72cc heads or 87 cc heads if flat top or small dish to use and keep 10.25 CR. Edelbrock RPM intake or Torker II.

As they said Dave at SD has all the stuff you would need and can even get you CNC ported heads and intake.

[rohrt]

1. Should I put forth the effort of rebuilding the motor, or look at other options: crate motor, LS swap, etc.?
2. If I pursue a rebuild of the Pontiac 400 block, what are some engine 'blueprint' recommendations to get me moving in the right direction? How much money would I really save by doing any possible wrench-turning on my own?

IMO You could go LS but your really going to have weigh out your resources for time/money and to research the conversion. I'm sure you could do a 5.3 swap in that $6K range and still hit your HP goals.

All good advice above.
If you stick with the Pontiac motor I think you can easily get your 400-450hp goal. What heads do you have?
Many of the small valve head are excellent candidate for large valves. Plenty of resources out there for self porting them as well. I just did a set of #15s for myself.
Most any Pontiac build will need forged rods and pistons at that point you might consider whether you want to do a stroker build as already mentioned. Plenty of info on the Performance Years forum.

The most budget friendly option IMO would be to stick with a 400. Rebuild it with budget forged rods, Autotech pistons with the metric ring pack, Summit 2801 or 2802 cam. Have the heads ported and get 2.11/1.77 vavles installed. Get a stock 4lbb manifold and get a rebuilt Q-jet. Then just have fun with it.

[Skip Fix]

#15s have a nice sized chamber for a 9.5:1 400. SD Performance even has CNC iron heads programs he can do for you.

You can get 400-450HP from a 400-it will take some better flowing heads ported iron or aluminum.

LS motors can easily make power but you can get some money in the whole package-and in 10 years will LS swaps be like TPI swaps form the 90s are now-not the neat thing? An original motor will always look right.

[paint2361]

I love my pontiac 440! I have it in a 67 Firebird which i freeway drive and autocross. In my case i did not wanna jump on the LS band wagon, But I do agree an LS is the best bang for the buck for engine swaps.

[yellow1098Greg]

I talked it over quite a bit, different combinations, improvements, etc to make to my 455 in my 71 Firebird. I've decided that instead of spending time to hunt different cranks/blocks, etc to make say a 440 (higher revving), and trying to find a machine shop to build it properly, and risking longevity, I'm just going to pony up next year for a Butler 461 short block for under $5k, but it'll be built by one of the, if not the best Pontiac people in the USA, and feature the parts they know will work. I figure hunting down a 400 block, and the other parts would cost me near $3k for a local machine shop build, if not more, than I'm rolling the dice as to whether they know what they're doing. I'd rather pay a little more and get the Butler name. Pretty much bolt on some Edelbrock or Kaufmann heads, and be done with it.

The LS is definitely an awesome engine, I'm a believer. But at least in my case, building my Firebird with anything but a Pontiac engine is not an option.


I'm planning on going this way as well with Butler....I already have the 87cc eheads...trying to get around 600hp...what would I need to get there? Just the right pistons and stroker setup? Or is that out of range?

[Skip Fix]

Flat tops and stroker rotating assembly crank depending on 400 3" ,main or 3.25 421/428/455 mains.