I am sorry if this subject has been beat to death, but i am about to pull the trigger on some major engine work. I have a 1978 Corvette L82. I have removed the cat and put headers and exhaust on the car. Other than that, i have replaced the fuel pump and changed the ingniton.

My question is this...should I do a Top End Kit from Edlebrock (PN 2022) which includes heads, cam, and manifold and combine it with a Holley 670cfm or should i go with a crate motor such as PN 19210008 which is a 350cid/330 HP. There is a little savings of going with the top end kit.

I am not worried about keeping car orignal...just want to make it run better. I figure i have added around 20 hp with the above mods, so at best i am pushing 240 hp.

I would love to hear some comments of suggestions.

Thanks

 

guess it depends on the condition of the bottom end of the existing engine, how many miles on the engine. With the crate engine everything is new. If you go crate hold on to the original engine. I also see there is a $2400 difference between the two at Summit Racing.

 

If the bottom end is sound then go for it.You can always reuse the top end on a new shortblock later if need be.

 

Like a 383

 

A few observations about that top end kit.
The supplied head gasket is a .039" compressed dimension head gasket. Combined with a stock block height in which the piston at TDC is .025" down the bore would give you a .064" squish height. Bad for detonation reasons.
At least the L-82 has a better piston design than the L-48. However you would still be around 9.2 CR if the L-82 has a 10 CC piston (unknown) volume with that head gasket, those heads, the stock block height and that cam.
Cam is flat tappet type with an older grind profile. Ok but not that good compared to what a roller could get you.
You would do better selecting the individual items seperately or modifying that top end kit a bit. That would also negate the lower cost of the kit packaging though.
It's hard to get a good bump with just a top end without having to rebuild the bottom too. If The rings are still good as indicated by a leak down test then it can be done to get maybe 350 HP max, probably more like 300HP to 330HP.
Crate motor is fine depending on what you're looking for and who you get it from. If your experience level and tooling is such that you can build your own that is the way to go for best results. Second best choice may be getting a trusted builder to do the work. Several people here have had good luck with crate motors as well though.

 

I just went through the same decisions on my 1981. After giving it more thought I ended up going with getting a local machine shop that was highly recommended and one of our local Corvette Club members worked there for 10 years. I am going to keep the engine mostly stock but it was recommended I go with a little higher compression piston and little beefed up cam, not much, just to stay within factory specifications. I am currently cleaning and detailing the engine compartment. In the future I am trying to find a good dual exhaust system I can install but still utilize the CCC/Computer.

Depending on the mileage you might want to think about getting the engine cleaned and machined. Mine was put through the cleaning tanks twice so far to get the 99,000 miles of black soot and junk off. :-)

 

Before I rebuilt my engine, I had driven it 50K. I knew exactly what I wanted in the next engine. I already had TFS heads and some other Hi Po parts. I needed a shop to do some mix and match.

I had one shop put it all together, then get it through smog!
No one else to blame, they were responsible for everything.
A turn key engine was the deal! Very happy.

A crate will have a warranty and will be all new!
I would still suggest having one shop put it together. That way if something goes wrong, you know who to call.

JMHO

R

 

I wrestled mightily with this same decision, went back and forth several times weighing the pros and cons. In the end I decided to keep my block and I ended up replacing just about everything. I am glad I went this way because the whole journey has been a blast and I got to do things my way, although with lots of advice from others. The posters above give good advice and I would probably end up echoing it, but to me the key is finding a good shop that you can work with. I scoped out three shops. I got the feeling from a couple of them that they only wanted to do things their way and not really interested in putting any extra thought into my specific project. In the end I went with a guy who knew SBCs inside out and was very passionate about his work. I was lucky to find him. A game changer though was when he checked my heads and found both to be cracked. I was lucky to find a decent set of used AFRs. I have between $3000 and $3500 into my engine here is what it looks like, just bolted on the carb yesterday.

Good luck

 

I would never buy a top end kit.
I prefer to find that parts that fit my engine, especially when if I reuse my short block.
You will get much more power, if you know what you have, and you buy parts that fits what short block you have (like REELAV8R is saying)
You will have a much better build, if you buy parts, that will fit your short block specifications.

 

I just went through this same exercise as well but pretty much decided that I wanted to keep my 78 L-82 4 speed-66,000 miles-all numbers match as much as an L-82 as I could, at least visually. I reused everything you can see except the AFR 180 64 CC aluminum heads such as the L82 aluminum intake, dual snorkel cold air filter housing, L-82 oil pan, L82 valve covers, etc. I pulled the engine myself, disassembled down to the short block (found a great engine performance guy near me-former GM field tech), had all the short block work done by him, and reinstalled the engine with just about everything new:

New Forged JE racing pistons/rings-.030
reconditioned L-82 forged Crankshaft
reconditioned L-82 rods
New bearings
New Oil pump
New Fuel pump
New Hayes Clutch kit-balanced
New AFR 180 64 CC heads
New Harmonic Balancer
New Motor Mounts
Howards Roller cam-.525/.525, Duration 219/225, LSA 110
New pushrods
Reused comp cams Roller tipped 1.52 rockers

Everything done on the short block-parts and labor-$3,500
Roller cam kit and AFR 180 heads-$2,500-I installed as well as the clutch

All in total was about $6,000-really not much cheaper than a GM crate motor BUT I used pretty much the best parts you can buy..the engine is a stormer. Non GM crate engines are cheaper BUT they don't use the best parts..it was a great experience and would do it again…I have an L-82 355 that has tremendous mid range power and will run to 6K easily and powerfully.

[IMG][/IMG]

 

[QUOTE=jb78L-82;1588966590]I just went through this same exercise as well...

If there was a "Like" button I would be pushing it right now. Looks great jb.

 

[QUOTE=Jim__H;1588967140]Your engine looks great as well. Did you use a flat tappet or roller cam-specs?. What about piston/rings, etc?

 

[QUOTE=jb78L-82;1588967183]jb;
Thanks. My plan was to build up a mid level engine, at least 9:1 CR, around 300hp and 340-350 ft-lb torque. When the heads came up cracked I opted for the used AFRs so that probably got me another 40-50 hp. My builder and I worked out various options as we went, here are the final specs:

• Bored out to .040 (already was .030" over)
• New Scat cast crank, reconditioned rods
• 9.2:1 CR (.015 deck height, .026 Clevite gasket), .041" squish
• The AFRs were 74 cc we took off .024: to get them to 70cc
• Sealed Power piston and ring set, 10cc dished for optimal detonation and flame propagation
• Lunati 10120702LK flat tapped cam and lifters, 219I/227E @ .050, 262I/268E advertised, .468I/.489E lift, 112 LSA
• ZZ4 intake manifold
• Rebuilt and modded Q-Jet per Cliff Ruggles Recipe #2
• Hedman 68301 headers, only ones that are legal in CA, have not bought yet
• Comp roller tipped rockers, push rods sized per the Straubtech method of 90 deg angle at mid lift

And pretty much all the new stuff that you did, harmonic balancer, oil pump etc.

I think that is about it.

Desktop dyno says all this will get me 386hp, I'll be real happy if that is true. And I am also going to replace my TH350 with a Bow Tie 700R4

I still have a lot of work to do on the car, especially the interior. I'll be lucky to have it running by late summer but hey this is fun.

 

Hyd Roller!

 

[QUOTE=Jim__H;1588968673]Thanks for the specifics. Funny I was looking at the lunati 262/268 cam at one time for my L-82 when I was going to do just the cam and clean up the stock 882 heads at one point. I used the felpro .015 head gasket with my 64CC heads and have about 10-10.2 compression with zero detonation with 87/89 gas. I sized my pushrods using the comp cams technique described on their website and my builder agreed--all has been fine at 600-700 miles on the engine with the rockers-I checked-everything is perfect so far. I would think that 350-375 Gross HP is reasonable looking at just the specs. I am guessing 425+ Gross HP for my 355-it pulls very hard mid range and lifts the nose of the car on acceleration….I do think that roller cam is the way to go for cam longevity and area under the curve HP/torque versus a flat tappet cam.

 

Yeah, I got plentu of hydraulic roller cam recommendations. It just wasn't in the budget especially after buying and refurbing the aluminum heads.