78-l82

I’m looking to get more horsepower out of a budget build (250-300 net HP would make me happy).

I have a 78, L82 with 4 spd wide ratio trans and 3.70 rear (freshly rebuilt).

Unfortunately, the motor is NOT the original L82. It was replaced with a Made in Mexico crate engine (block casting # 10066036, heads casting #14034808). I don’t know why, I’ve only had the car 3 months and the previous owner didn’t know much about it either.

The intake is the stock (#458520) L82 aluminum intake and the original Q-jet.

The exhaust is also stock with the 2-1-2 exhaust and the cat. I plan on converting this to a true dual setup but I want to keep the stock look and stick with the stock ram horn exhaust manifold.

I also want to keep the L-82 valve covers, the Q-jet and intake if possible.

Basically, I want to keep it looking like an L82 engine but upgrade the heads, exhaust and later the cam (when I pull the radiator to replace that).

Someone is selling 492 heads for $250. “1970 Chevy 350 heads 2.02 bowtie (cammel Hump) 64cc casting #492 ported and polished by eddies vale grinding complete ready to run less than 3000 miles”

Will the 492 heads work with the stock L82 aluminum intake and Q-jet carb? The heads do have the accessory holes.

Thanks for your input.

p.s. Please don’t make this about the 492 heads being old technology. I’ve read those threads/posts. I’m only looking for 300HP tops (If I get more, great but this is a daily driver). The 492 heads drop me from 76cc to 64 cc and increase the intake and exhaust flow. I should get more HP out of these heads over what I have and for $250 I think that’s great. I’m more concerned if I’ll have to change the L82 aluminum intake to fit the 492 heads.

Shark Racer

Everything should bolt up just fine. You probably won't make the 300 net HP mark with those heads and stock manifolds.

Are the heads guaranteed to run, not leak past the valve seal, no cracks, etc? $250 isn't much, but if you have to turn around and invest another $200 in getting them ready to install, the numbers will start creeping up and you'll wish you just got something else from the get-go.

Ganey

Yes & you should replace the cam w/ at least L-82 cam which will make a big difference because it is likely the replacement engine had a std. cam.

Ben Lurkin

Will they work? Yes. How well is the question.

Get a pair of vortec heads for your build for about the same price. Why use fourty year old flow technology which is what you will get with those 492 heads.

The only reason to use those heads is for a NCRS type restoration IMHO.

billla

I would give it a miss; I can't see any real gain for the time and expense of the swap.

I typically find that about 90% of the heads on CL are junk that someone else screwed up or they're just shot. Unless you have the skills to fully inspect the heads or they're willing to let you take them to a shop...I would pass.

78-l82

I know buyer beware and these inexpensive heads could be a money pit but that's something I'm going to have to see when I inspect them. I still think I'll be ahead if I have to spend $200 to get them ready to install.

As for the vortec heads...I don't know where I could get vortec heads for $250 (even $500). Plus, I would need a vortec compatible intake. I want to keep a "stock" look with my stock aluminum intake.

Ben Lurkin

By the time you get those 492 heads done, you will be into them more than $250! They will net out more than the Vortec heads since they don't have hardened seats, will likely need guides, springs, a few valves and a valve job. At a minimum, get them checked for cracks BEFORE you buy.

Do you have a salvage yard anywhere nearby? The Vortec heads were used on 96 up applications so they aren't rare by any means. In factory form, they're good for somewhere around 400 hp! Around here $200 will get you a set. Add a valve job and drop 'em on. I don't know what you mean by "stock look" unless you're referring to the older intake bolt pattern. You have an hecho en mexico block already. Unless you're doing a true restoration, there's no point. But if you want to go slow(er) and spend more $$$, the 492 heads will do that for you.

78-l82

I'm really taking a beating on these 492 heads.

They are supposed to have been ported and polished, magnafluxed (no cracks) and new springs. This was all done at a local shop. They have 3000 miles on them since the work.

If I go with them I'll take your advice to get them checked out before I buy them. They seller doesn't have the receipts for the work (I asked) but the shop might still have the records of the work. If everything is as the seller states they are ready to bolt on and go (now there is obviously the work that would need to get done when replacing any heads...but that is the case with any heads I go with).

By "stock" I mean I want to keep the aluminum intake and q-jet. With vortec heads I would need a different intake and probably a different carb.

The salvage yard is a good idea. I have one that is close enough that a friend of mine is always going to.

69 Chevy

They will work fine. However, according to Chevy Performance Volume 1, the #492 'replacement' Z-28 heads "...has a minimum volume per cylinder of 61.2cc... That might affect the compression ratio on your mexican short block.

As was mentioned, a stronger performance cam would be in order. However, if that's not in your immediate budget, here's something to think about: having big valve heads does no good if you're not able to open them all the way. OEM rocker arms are listed as 1.5:1 ratio but in reality are more like1.38-1.4:1. A cheap set of true 1.52:1 aftermarket rockers would go a long way in utilizing the performance built into those #492 heads. Depending on your piston design, 1.6:1 would be a big improvement in cylinder breathing.

INMYBLOOD

I like this idea if your set on the 492's and no cam change. I'd bet he could get away with the 1.6:1 with a target motor cam. Might as well but in thin head gaskets too.

hugie82

If its Eddie's Valve grinding in Sayerville NJ (if I spelled it wrong its BonJovi's home town) They have always had a good reputation. If they are a fresh rebuilt heads I would check the deck for pits, rust and use a straight edge with a .005 feeler gauge to check for warpage. A cheap set of 1.6 rockers and good head gaskets you should be good to go!

78-l82

can you please recommend a part # for the rockers? The only consideration is I want them to be able to fit under the stock L82 valve covers so I think that excludes some of the roller rockers.

I eventually want to replace the cam but I while I have the hood off and radiator out I want to do a few other things so I'm going to hold off and make that one big project.

Still looking into a shop to look at the heads before I buy them. As for the 492s overall, people either love them or hate them.

And yes, the person who is selling the heads had a typo. They were done by Eddie's Valve grinding (not vale).

Ganey

Comp Cams 1412-16

GUSTO14

I have been running these Crane Energizer Rockers under stock aluminum valve covers for almost 20 years now with no problems.
http://www.jegs.com/i/Crane-Cams/271...rentProductId=
I did recently swap out valve cover gaskets as part of a general PM and went with a set of FelPro double thick gaskets, but again no clearance issues.

Good luck... GUSTO