[FormulaSlade]

Starting my 71 400 build. I have a 481988 short block, stock rods, 2227P TRW 030 forged pistons, stock crank. Heads 96's, and have had some mild porting/cleanup done on them and have port matched the intake as well. Would like to get a solid 400-425 hp, not really wanting to run sub frame connectors if possible. I'm 49, and my car pounding days are over. This car is a really nice rust free, 1 owner 76 formula. Just want to roast the tires when I want, or pound the ground at the shows... Any suggestions??? Thanks...

[mchell]

In my opinion, 400 to 425 hp with a very mild, stockish,low compression 400 engine is going to be a stretch..... I would mill those heads to get some compression.....run a 3.55 gear and a good stall converter.... And of course all the other acoutrements, such as a well chosen cam, headers, good exhaust system, etc.....then have fun

If that dont float your boat and ya want to keep it stock to cruise around....no problem....it just ain't gonna be a real tire shredding monster .....you may be left wanting

[FrankieT/A]

Correct me if I'm wrong but aren't TRW forged pistons for a 400 L2262?

[FormulaSlade]

What about, changing the crank and rods, like a 440, or something close. As well as shaving the Heads and decking the block. Just want to use as much of what I have already. Will also be running a roller type cam kit... My buds dad owns a machine shop, pretty grew up around there. So decking and shaving are no problem...Thanks...

[WARPed]

Originally Posted by FrankieT/A

Correct me if I'm wrong but aren't TRW forged pistons for a 400 L2262?

In 75 (or was that 76) Pontiac dropped the CR by beveling outer edge of the piston top - hence the different piston part number.

[FormulaSlade]

Part # 2227P is an old part number for TRW forged replacement pistons 30 over....

[WARPed]

Originally Posted by FormulaSlade

What about, changing the crank and rods, like a 440, or something close. As well as shaving the Heads and decking the block. Just want to use as much of what I have already. Will also be running a roller type cam kit... My buds dad owns a machine shop, pretty grew up around there. So decking and shaving are no problem...Thanks...

You could get a stroker crank but the current pistons would have to be replaced. Also do not go over 9.5 CR with pump gas and iron heads.

[72blackbird]

X2 on getting 400 hp from a 8:1 400- you're gonna have to get a really expensive port job or turbo it to make that happen with what you have. And even if you had 270 cfm ported iron heads you're have to rev it hard with really aggressive can to get close to 400 hp- too much work and money just to make it happen with your existing parts.

IMO it's much easier to stroke it to 455, use low-cost 455 pistons and forged rods (they're too cheap not to use- toss the cast rods on the scrap pile). Upgrade your heads with stainless 2.11/1.77 valves, competition valve job, bronze guides, add a PPR TC-01 HF cam and you're at an easy 400-425 hp.

[FrankieT/A]

Big time on the rods!!!

[android 211]

Rochester, cast iron intake, '96' heads mildly ported/cleaned up but milled as little as possible, 400 block zero decked, stroker 455 crank, forged rods, RA IV cam advanced 4 degrees, cast flat top pistons, recurved HEI. RA manifolds or headers.

[72LuxuryLeMansLa.]

Originally Posted by FormulaSlade

Starting my 71 400 build. I have a 481988 short block, stock rods, 2227P TRW 030 forged pistons, stock crank. Heads 96's, and have had some mild porting/cleanup done on them and have port matched the intake as well. Would like to get a solid 400-425 hp, not really wanting to run sub frame connectors if possible. I'm 49, and my car pounding days are over. This car is a really nice rust free, 1 owner 76 formula. Just want to roast the tires when I want, or pound the ground at the shows... Any suggestions??? Thanks...

If you don't mind milling the heads I think you could easily do this. Taking .050" off of stock 96 heads (96cc according to P-dude) would get you to 86cc. That along with cheap forged rods ($300) and 8cc Forged Flat top pistons ($500) and zero decking the block would get you to 9.05:1scr. Not a dangerous scr by any stretch but enough to make decent power.
I'm no expert but that's my opinion....

Karl

[72LuxuryLeMansLa.]

Originally Posted by 72LuxuryLeMansLa.

If you don't mind milling the heads I think you could easily do this. Taking .050" off of stock 96 heads (96cc according to P-dude) would get you to 86cc. That along with cheap forged rods ($300) and 8cc Forged Flat top pistons ($500) and zero decking the block would get you to 9.05:1scr. Not a dangerous scr by any stretch but enough to make decent power.
I'm no expert but that's my opinion....

Karl

I would also guess that the Crower 60242 HFT cam would be a good fit for the build I am recommending if you are using an automatic tranny and street type gearing/converter set up. Experts can tell you weather or not 9:1 scr is enough for this cam, I think it is.
Remember I am no expert just testing my ideas against those with more knowledge and experience.

Karl

[mechanic17]

Here's another direction to consider.

You don't need to stroke it, nor do you need to shave the heads if they're in good shape already. 96cc are a good middle-chamber size, and you have the big valves. You said they've been cleaned up and port matched. I wouldn't "molest" them further and risk screwing them up.

I'm assuming because you already have a lot of good parts you aren't wanting to spend a lot. A little detailing and the right cam choice will get you there.

I would say three things are a must: 1) zero decking the block, and 2) detailing the crank. Stock cranks do fatigue over the years and break with spirited driving. A balancing job will help too. If you're not confident with a die grinder, get a good machine shop on it (you'll need one to get the block right.)

3) The exhaust has to be good on the car. I'd recommend RARE, 2.5 outlets, best that will fit the car, long branch if possible. This costs money, but you need it no matter what motor you build.

You'll be at about 8.5 SCR then, and the XE cams were made to get the cylinder pressure up. A XE274 will give you the 400 hp, but given your intended usage, I think you'll be happier with the 268 and 375hp, but more torque under the curve.

Cam gurus may favor another cam (lots of XE bashing here) but the point is to stick with a mild 50-60 degrees overlap and get your DCR up.

With this plan, you're not buying expensive new parts, but putting your budget into getting important stuff right which would have to be done anyway. Now, if your crank was questionable anyway, you could kill two birds by stroking (which will raise the SCR,) but you're in for a whole new set of pistons, and your machine work STILL needs doing.

[paul s.]

Slade, as we all know, hp and torque is all about cylinder pressure. Period. With the low compression heads and 400 inches you are at a distinct disadvantage when you are looking at achieving a real 400+hp. So, yes, if you are going to keep both the heads and the displacement, then get those heads down to around 85cc's and zero deck the block. There are other consequences from milling a large amount of material from the head deck such as manifold alignment.

The absolute EASIEST way to make the power you want is to stroke it and throw your unmolested heads on top of that bigger cube shortblock. More torque, more compression, stock or mild convertor, mild ignition timing, highway gears,and no custom milling. Just a straight-forward assemblage of parts.

You will get AT LEAST 400 just putting it together. Start blueprinting with a decked block, proper spring pressure for the cam to be used, port-matched intake, and a good exhaust, and you will feel the difference as all of these things add up.

Good luck on your build

[Poncho-V]

I too, have a '71 400 with the 96 heads. Airflow equals horsepower. The more air you can move through an engine at any given RPM, the more horsepower you will make with any engine. Don't forget port velocity! A good valve job by a competent Pontiac head porter, along with a good valve job and zero decking the block and pistons with only 2 valve reliefs, and the heart of ANY engine, the camshaft, and 400 - 425 horses is EASY!!! No need for stroking...

[Formula8]

Originally Posted by android 211

Rochester, cast iron intake, '96' heads mildly ported/cleaned up but milled as little as possible, 400 block zero decked, stroker 455 crank, forged rods, RA IV cam advanced 4 degrees, cast flat top pistons, recurved HEI. RA manifolds or headers.

X 2, except if you are going that far, I would go with forged pistons and quit being a wuss. I hope being 49 does not put the racing days behind anyone if that is what they chose to do. I get that it is not your thing but the above combination has proven to be reasonably priced and deadly effective.

[FormulaSlade]

Formula8, thanks for the input. But, if you would take a look and read the parts listed you would see that the pistons are forged. As far as your wuss comment, grow up dude...

[PunchT37]

I would mill those 96 heads as a last resort. They are a one year only head and a lot of stroker or 455 are looking for them, as well as the`71 GTO resto. guys.

I would go with the 72cc Edelbrock d port heads and a 230`ish at 050 cam to get your 400 hp.

[PunchT37]

If you keep the 96 heads, get a good valve job and maybe some pocket work. Get a real flat top piston, none of this 389/400 application bullsh!t, and run a Comp XE268. You`ll have a decent running street 400.

[HWYSTR455]

I too agree that stroking it would be the best route.

You need rods, because the factory ones are too much of a risk, and machine work on the factory ones would be more than a new set.

Same with the crank, to do the machine work, you're almost all the way into paying for a cast stroker crank.

The TRW pistons are heavy, and not an optimum choice. You can eBay those are recoup the cost of new ones.

If you do use the parts you have, you will still have to deal with the static CR being low. That would compromise your cam selections, and limit your output. Period. It's much easier to go with a proven stroker combo, and you can exceed the power goals you have set, as well as have a 'proper' configuration. And it will cost about the same.

.