Thread: 327 sj for a 78 nova

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Originally Posted by bluepyro

also which rpm intake should I get for this combination
and which set of 1 5/8" long tube headers should I get? thanks for the help guys without youi would be running in circles and getting nowhere.

Edelbrock #7101 for conventional Gen I heads mounting a square-bore carburetor. The very same manifold can be had under Holley part #300-36 and Weiand 8016. Neither of those manifolds is being made any longer, but many times they come up on ebay or craigslist.
Edelbrock #7104 for conventional Gen I heads mounting a spread-bore carburetor such as a Rochester Quadrajet.
Edelbrock #7116 for Vortec heads mounting a square-bore carburetor. Counsel with head supplier, find out whether the heads take a Vortec intake or a conventional intake.

Concerning headers, you want a quality set of long-tube headers. Not shortys. Look for 1 5/8" primary tube size and a 3/8" thick flange. Thinner flanges will curl up from the heat and spit the gasket out. It's up to you whether you want them painted or coated with Jet-Hot or some other protective coating.

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Lots of information in this post and a builder willing to follow. With his iron heads what kind of torque curve do you expect and a guess on horsepower? The RPM limit he should observe? Thanks Tech

Although tech and I have disagreed on this, IMHO an Offenhauser #5693 square bore or #5744 spread bore are better manifolds.

Originally Posted by Scooting

Lots of information in this post and a builder willing to follow. With his iron heads what kind of torque curve do you expect and a guess on horsepower? The RPM limit he should observe? Thanks Tech

If I had some valid flow numbers on the heads, I might venture a guess on hp and torque. The cam will pull to 6000, so that would be a nice round figure to set the rev limit of the motor.

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Originally Posted by techinspector1

If I had some valid flow numbers on the heads, I might venture a guess on hp and torque. The cam will pull to 6000, so that would be a nice round figure to set the rev limit of the motor.

Tech, JEGS shows a little flow chart for the 2151 head, if that gives a good enough idea on the flow? - ProMaxx Performance 2151 Patriot Performance GM Vortec 185cc Cylinder Heads - Free Shipping on All Orders @ JEGS

Originally Posted by rspears

Tech, JEGS shows a little flow chart for the 2151 head, if that gives a good enough idea on the flow? - ProMaxx Performance 2151 Patriot Performance GM Vortec 185cc Cylinder Heads - Free Shipping on All Orders @ JEGS

Thanks Roger. Looks like about 230 cfm @ 0.400" intake valve lift, so if you had enough cubic inches suckin' through 'em, they should be capable of making 450+ hp. With this little 327, I might expect 375 hp and 400 ft/lbs of torque.


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Originally Posted by NTFDAY

Although tech and I have disagreed on this, IMHO an Offenhauser #5693 square bore or #5744 spread bore are better manifolds.

You might be right Ken, I just have never seen a dyno flog with either of those numbers.

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Originally Posted by techinspector1

You might be right Ken, I just have never seen a dyno flog with either of those numbers.

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I might be wrong, but I think everybody else copied Offenhauser's 360 design. The stock manifold on a 67 Z comes to mind.

Ok today I jacked up the rear end of the nova just to make sure its posi traction. I was told it was but I bought a lesson its not a posi. When one wheel turned the other stayed still. So my question is can I just rip out the old gears and install a 3.73 posi and put in and auburn locker 0r will I have to do some digging and find a posi rear end. then put in the correct gear ratios and auburn locker.

that's not a good test-------------some posi type rears need to have some resistance to work-----------they are limited slip, not positive--------

Unless your gears are bad you're throwing money away replacing the ring & pinion. The ring gear bolts to the carrier, and the carrier is where the differential action takes place. What differential do you have, one with a pumpkin or one with a rear cover to load internals? Either way, you need to know what you've got, and if you decide to replace the clutch type posi unit take a look at the Detroit Eaton TrueTrac helical gear type - closest to a locker, and virtually bullet proof.

Tech1, thanks for the link to the ZDDP additive. To the person who started this thread I say STUDY the details of Tech1's first reply, it is excellent advice in a short one page reply. You can buy David Vizard's "How to Build an SBC" book and not find as much concise advise in one page. I am a big fan of ZDDP for flat tappet engines. Some laws say it is illegal and will spoil catalytic convertors but if you have a rebuilt flat tappet engine with good compression the oil should not make it to the convertors for many thousands of miles and strictly speaking ZDDP is legal as long as the engine is a flat tappet design. Local quick oil change shops are crazy in my view because they will not install anything but 5W-30 and no ZDDP. Thus you have make you own formulation and change the oil yourself.

Don Shillady
Retired Scientist/teen rodder

I have the one with a cover 10 bolts if memory serves ill have to check when I get back to the garage

those posies are all over the place and not hard to install.

if running a flat lifter cam do not be cheap buy oil made for break in or buy race oil as it has zddp in it . its not good to run threw cats it will plug them has a new engine may use some oil will get in by the PCV for starters.there were many flat lifter engines that had cats on them so it.s not a law were you can run zddp oil if it.s a flat cam engine . less you core out the cat then you can get a nice fine for doing so . as for the neat can of zddp it could just sit in the bottom of the oil pan has there a fast burn zddp and slow burn with a hi detergent oil added to the mix it will never bond so less you can check the parts to know for sure the can of wiz bang snake oil your getting is bonding the zddp to parts your pissing away your money do not take my word on this go to joe gibs oil web page . as i build engines for a income and they make oil