My friend and I just bought a 1972 Nova put a new engine into it but it's not running as fast as we thought. It is pretty much a L-82 engine from a corvette gone through. Balanced, blueprinted, and bored .030 over with flat top pistons. It has a Comp Cams xtreme energy 268 cam with .477/.480 lift and on top has a holly dual plane hi-rise with a holly 650 double-pumper. We found some 1 5/8 dynomax long tube headers and I bolted my old thrush glass packs to them. It's running the stock TH-350 with a 2000 stall and a 3.42 posi 8.5 10-bolt with 9x26-15 slicks. The car weighs about 3300lbs w/o driver. The first time we took it out, I ran a 14.52@93mph. We've been reading articles in some magazines and have seen cars with similar engines running better times. We think it's the heads so we are looking for some input. We're thinking of the 58cc aluminum L-98 corvette heads, the vortec heads or the Dart Iron Eagles. Which heads should we use and if we're going to put a little juice to it (125-shot), would that make a diff.

I would go with new heads at this point IMHO. I think the glass packs are not doing you any favors either. They are a HP robber over a better muffler setup.

-Mark.

Iron eagles will make more power then the vette heads and the vortecs, and also have a bunch more power potential later - when ported.
If youre on a budget look for some good used aftermarket aluminum heads.

I am able to get a pair of some 200cc/64cc Dart Iron Eagles with 2.05/1.6 valves for a smoking deal. Any input?!?

Go for the heads b/c they will allow you to grow later.

As for the glasspacks they are great if they have smooth, perforated inner core pipes that are the same diameter as the muffler's in and out dimensions, but not if they have pressed or chop-sawed louvers that choke the inner pipe down smaller!!

Walker/Dynomax/thrush Continental type are the good ones that I always refer to.

pdq67

Those Dart heads should be just the ticket. I bought a set of those for my L-82 this week. That will up the compression quite a bit so a cam change may be in order.

-Mark.

How's the ignition curve?

I was recently talking to a guy who dyno tested his 327 Corvette with Hooker sidepipes. The addition of the glass-pack muffler into the collector cost him over 100 hp at the flywheel. Bolting a glass-pack muffler directly onto your collector is a similar move.
At 93 mph you are running less than 4500 rpm in third gear, given the 26" tire and about 5% converter slip. If you get your speed up to 107 mph you will still only be running 5000 rpm in the traps. I would concentrate my efforts on improving the torque in the 3500-5000 rpm range by adding longer primary tubes, a smaller collector, X-pipe, etc. We've seen some very impressive numbers from Vortec heads on our chassis dyno, especially on the 350" motors.

There are some dart iron eagle 180cc heads for sale at a local speed shop. The only thing is that they are 49cc 2.02/1.60 heads. I don't know if the comp. ratio would be too high or we could put thicker head gaskets. Engine is a zero decked 355 w/flat tops if you forgot.

What speed shop would that be? We are looking for some 180cc heads with a small combustion chamber for an altitude motor.

I like onofakind67's comments about the exhuast. I would toss into the hat the notion that those "other cars with simalar engines" likely also have very little slop in the chassis IE frame connectors ( cheap ) poly bushings ETC. What has your econo racer had done to account for this? Also I am a bit old fashioned but I think a Turbo 350 has a 2.5 or so low gear ratio and would also check the other cars to see about the 3.42's. I think more gear would help a bit as well.

See the truck in my sig? 15.08@95.65mph, with a blazing 60' of 2.39 :rolleyes: I am running 275/60-15's street tires, a weak posi, and over 1000 pounds more than your nova. Something is amiss here. I would definately lose the glasspacks unless they are like PDQ said and have the same ID perforated cores. I have always noticed a considerable difference in power switching from the louvered glasspacks to even cheap "muffler shop" turbo mufflers even on mild toque-type truck motors. Most header muffler type glasspacks are only 2" ID, with louvered cores to boot. Definate power killers. Those heads aren't doing you any favors either, but at this point they aren't hurting you too badly.

Is there any input on the dart iron eagle angled plug heads? I heard that there are some heads out there that require special headers to clear the spark plugs and also to be able to change them w/o having to unhook the headers? Does anybody have these heads, and how do they combine with regular long tube headers on a 72' nova???

You could take your headers to the speed shop and try them on for size. They might fit fine.

By the way, you will have WAY too much compression with those heads. Somewhere around 12:1 to 13:1 or so by my quick calculations. :(

-Mark.

What is the casting number on the heads you have now/ valve size. Wouldn't a 200 cc runner loose some velocity over the vortec runners, runners in the heads he has now. Also what was the 60ft?
My car would stall out and just about die when I floored it, it had a 1900-2000 converter. I also agree that some more gear would help.