[LOPEZ5]

I'm sort of new at this. What I'm looking to get out of it is education. With me there is a lot of room for improvement. I'll start by asking about my car. I have a '72 LeMans Sport 2dr hardtop with a 400cid engine off a '74 GP. I know the HP and engine compression out of the '74 was sort of low.(184 and 7.6 I think) What I'm looking for is to increase the comp and up the ponnies, maybe 300 to 350 Hp. Where do I need to start? What do I need to look for as far as engine #'s, gears, etc, etc.
Any contributions to my Pontiac 101 class is greatly appreciated. Thanks

[LOPEZ5]

I'm sort of new at this. What I'm looking to get out of it is education. With me there is a lot of room for improvement. I'll start by asking about my car. I have a '72 LeMans Sport 2dr hardtop with a 400cid engine off a '74 GP. I know the HP and engine compression out of the '74 was sort of low.(184 and 7.6 I think) What I'm looking for is to increase the comp and up the ponnies, maybe 300 to 350 Hp. Where do I need to start? What do I need to look for as far as engine #'s, gears, etc, etc.
Any contributions to my Pontiac 101 class is greatly appreciated. Thanks

[ricbrooks2]

The easiest way to up the compression is simply change the heads to ones with a smaller combustion chamber or CC. I would not look for ones dated 1970 or before because that compression will most likely be too high for pump gas. Look for ones dated 71 and later that have the screw in rocker studs. The screw in studs will help later when you put a new cam in and need to adjust the rockers.I 'll look for a link with the head information and post later for you.

[ricbrooks2]

Here is a very helpful link. It breaks down the heads by number and lists CC's.
www.boyleworks.com

Click on muscle cars then click the Indian head and scroll down to head identification. This site is a wealth of good info.

[meanolgoat]

Someone correct me if I'm wrong, but I believe that by 74, they had switched from Flywheel Horsepower readings to Rearwheel Horsepower readings. So if your goal is 300 to 350 at the flywheel you're not that far away.

[uneasyrider]

In 1972 SAE net hp was rated at the tail shaft of the transmission with the AC and any other option (including the alt.) turned on. It was averaged between 4spd and auto. cars. This gave a “more realistic� hp rating than the gross hp ratings of the muscle car era. Before SAE net they would measure the hp at the flywheel with out even a water pump or alternator attached to the engine and “open� exhaust a lot of times. The problem with SAE net is that they never set stringent enough guidelines on exactly how to measure it so it has been “doctored� many times in the resent past to give falsely higher hp claims. The Ford Mustang is a good example of that. A few years ago they were caught “doctoring� their advertised hp and rating it several hp higher than it was to compete with Chevy’s Z28. As a rough figure you can add 20-30% to the SAE net figures to get what it would be in “’60’s� hp. The problem though with trying to directly compare ‘60’s hp figures to ’70 and later figures is that a lot of the ‘60’s cars got under rated for insurance purposes. Example: 426 hemi was rated at something like 425hp at around 4,500rpm. The engine was capable of making hp clear up to around 6,000rpm. This actually meant that at 6,000rpm it was pushing out closer to 500hp. Now if you knock 30% off that figure to get rear wheel horsepower (NOT SAE net, SAE net is NOT at the rear wheels) you get approximately 350hp at the rear wheels. I was watching one of those Dream Car/Two Guys/TOO MUCH MONEY shows that dynoed a real Hemi Cuda and it put down 320hp at the rear wheels so the calculation isn’t a bad rough guess.

I got a buddy that has a '70 Road Runner that's putting 414hp and 458ftlbs to the rear wheels. Given that the car is manual trans. and no options I'll say it burns up 20% to the rear wheels so that's about 496hp at the flywheel.

For 184hp at the tail shaft of the trans. and AC guessing 20% loss 220hp at the flywheel.

[firebirdmi]

Have a 400ci with milled #96 heads from 1971. Runs just fine on 87 octane. The combo works well and with a 230 duration cam @.05 lift, rhoads lifters, and headers/3" exhaust it has a some giddy-up.

[samssuperpro]

Put some 62's on it off of a 69 400

[LOPEZ5]

Thanks for the input guys. Rjb, that website you gave me was a wealth of info. Now I know that the 4X heads I have are not the best option. Meanolgoat, I'm looking to get to 300 or 350 Hp at the rear wheels. Michael, where and how much(approx.) for the 62's? I had the 64's in mind with a 230 duration @ .05 lift cam. As well as rollers, no brand yet.
Keep the info going, I'm soaking it all into my brain. Thanks again.

[uneasyrider]

There was a good artical in HPP mag. on a nice build up for a street smog era engine in the Tech section. Lots of very good build info. in general in this months HHP to look at for some ideas.

Good luck,

Uneasyrider

[Ollie]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Michael, where and how much(approx.) for the 62's? I had the 64's in mind with a 230 duration @ .05 lift cam. As well as rollers, no brand yet.
<HR></BLOCKQUOTE>The #64 heads are rare and expensive Look for the #62 heads, They are more common and reasoniably priced. check Ebay there are some on there now

[LOPEZ5]

Hey Ollie, I checked ebay, the 62's that are there are really 538177's off of a '62 389ci. I did find some 13's off of a '70 judge. They're asking for $320. Is that reasonable?

[Mr. P-Body]

A '70 Judge had either 12s or 614s. 13s were on 350 horse engines. Even the automatic transmission cars had 12s.

[LOPEZ5]

Mr. P-Body, maybe they're not off of a judge, but would that be a suitable set for what I want? Would I have any problems with the intake, or the manifolds? If $ permits, I'm considering the Edelbrock Performer intake and some headers. I'd like Doug's headers, but we'll see...

[Darrell]

1970 judges with Ram air 3 auto tranny's had 13 heads.

[LOPEZ5]

Hey Darrell, so is that set of heads on ebay a decent purchase...

[racerboy]

Canis,
Welcome to the PY boards. I think $320 for a set of # 13s is a pretty good deal.

13s had a 75 cc chamber, so you are probaly right on the edge of 10:1. May want to consider opening up the cahmber a bit when you have the heads rebuilt.

Doesn't sound like yuo need anything exotic. If this is for a street car, I would go with an 068 cam, an early (68-71) stock 4-barrel intake, a set of Ram Air exhaust manifolds and have Cliff set up a good Q-jet for you.

Also, buy Jim Hand's book! PY sells it and it is worth every penny.
-----------------------------

Darrell,
Did your Judge come with 13s? Have heard of folks saying auomatic RA III cars may have had 13s, but I never actually saw any factory documentation to support this.

I only buy 4-speeds.

racerboy

[LOPEZ5]

Racerboy,

thanks for the input, that's pretty much what I was looking for. Simple, but effective. I think this combo on parts is less damage on the money, and keeps it all Pontiac, instead of aftermarket parts, like Edelbrock intake and heads, and Comp Cams stick. Your right, it's a street car, minimal strip action if any...

[Dragncar]

Here are some numbers I got from a machinist who worked for Pontiac as a mechanic in the late 60s early 70s.He checked the CCs on the heads back in the day before they ever got a chance to be milled. (16s 74cc)(12s 67cc)(48s 65.5cc)(13s 77cc)(62s 75 cc)(64s90cc).Pontiac lists many of these heads as 72ccs but they are not.With a flat top TRW without the big bevel a #13 will get you 9.3 CR and the #62 9.5 CR on a 400.TRW makes a piston with a big bevel that will drop the compression so #16,#12 will work as does Kieth Black.By the way I have pairs of all of these heads and could sell one or two if anyone is interested.

[LOPEZ5]

HEY DRAGNCAR,
that's some good data, thanks. How much for a set of 13's... I haven't checked out the eBay for about a month, but if you have them, I'm interested. You can send me a msg to [email protected]