1964 L76 vs. L84

[Michael J.]

I will soon get my "new" '64 L76, and since I know nothing about that year and engine, I wanted to ask the experts what the differences are between its' L76 engine and the L84 FI engine. They are listed as being within 10 HP of each other, just wondering what the engine differences are besides the obvious intake system, thanks!

[William C.]

Re: 1964 L76 vs. L84

Virtually none except the FI vs carburetor.

[Mike E.]

Re: 1964 L76 vs. L84

A few years ago Vette Magazine asked the same question. Well kind of.

http://www.vetteweb.com/tech/vemp_0911_l84_fuelie_motor_on_engine_dyno/

Mike

[Michael J.]

Re: 1964 L76 vs. L84

Thanks guys, just what I needed. Mike, that article is great, too bad it wasn't exactly the same as the old school engines, but close I guess. Interesting about the cam swap with the Duntov cam, I wouldn't have thought it would have improved it that much over Duntov's engineering, but modern technology.....

[Duke W.]

Re: 1964 L76 vs. L84

The FI manifold is much more efficient than the SHP manifold, but head flow is the major restriction so FI only makes 2-3 percent more top end power with Flint-machined heads. A good head massage will double the advantage.

BTW, the camshaft referal as a "Duntov 30-30" is a misnomer. The only "Duntov" cam is the '56-'63 OE mechanical lifter cam. The 30-30 was not personally designed by Duntov like the ...097, but I'm sure he had some input.

The other thing to remember is that the performance curves will be significantly different with manifolds compared to the large tube headers they used. Torque and power will be down through most of the range except for the bottom end, which, of course, they didn't test.

Headers make good use of wave dynamics to scavenge the cylinder during the overlap period and relatively high overlap is good. Manifolds don't like overlap, and the less the better for any given duration.

Duke

[Michael J.]

Re: 1964 L76 vs. L84

Thanks Duke, I guess that same head message would also help the L76? Just not as much as the L84?

[Dick W.]

Re: 1964 L76 vs. L84

Plus you do not have all the inherent maintenance issues with a carburetor that you do with fuel infestation

[Dan H.]

Re: 1964 L76 vs. L84

FIs aren't that hard to maintain, they offer equal fuel/air to each cylinder, WAY better than any carb set up. The parts are very available and some are an improvement on Rochesters parts. Have had both setups, really like the FI for all around driving etc. Run my 64 on pump gas, maybe a little Marvel Mystery oil just for the snake oil lovers!

[Duke W.]

Re: 1964 L76 vs. L84

Thanks Duke, I guess that same head message would also help the L76? Just not as much as the L84?

Yes, but once you massage the heads on a L76 the inlet manifold is the next biggest restriction, which is why FI pulls further ahead. The LT1 manifold in place of the 327 SHP manifold will make up most of the distance.

Duke