gears and converter for an L78 cammed big block

[luzl78]

Originally Posted by 2MQ

I know this is splitting hairs, but in a 454 that is an LS6 cam.

same cam

[WILMASBOYL78]

I would think a 3.55 - 3.73 range with a quality convertor 2600-2800 would do the trick. You might want to check with ATI and give them your specs and possible rear gears and see what they recommend. Another thing to consider is the transmission...is it bone stock? shift kit? performance governor?...

The original L78/LS6 packages had a HD TH400, 6 lug convertor and a special governor that allowed for high rpm shifts...around 6200 rpm.

If the rpm's don't scare you, then 4.10's will really make it jump.

-wilma

[aaronkl84corvett]

yes it is the LS6 Cam..

its an Elgin copy - E905P (if i remember correctly - but the specs are spot on)
i have it degreed in 2advance

i have the old log type manifolds on the car which I'm sure is killing it above 4500 rpm - really don't wanna go with headers, but i'd consider going with the long branch corvette style that I believe will fit.

i have a set of 3.73s for the car - will install them this summer.

converter now is a B&M holeshot 2400 - but it could probably be much happier with a 3000 converter for quick starts - i just don't like that slippery converter feel for a nearly daily driven vehicle.

[WILMASBOYL78]

Originally Posted by aaronkl84corvett

yes it is the LS6 Cam..

its an Elgin copy - E905P (if i remember correctly - but the specs are spot on)
i have it degreed in 2advance

i have the old log type manifolds on the car which I'm sure is killing it above 4500 rpm - really don't wanna go with headers, but i'd consider going with the long branch corvette style that I believe will fit.

i have a set of 3.73s for the car - will install them this summer.

converter now is a B&M holeshot 2400 - but it could probably be much happier with a 3000 converter for quick starts - i just don't like that slippery converter feel for a nearly daily driven vehicle.

You need to consider that the street mechanical cam that Chevy used in the L78/LS6/L72 was designed to be used on engine with cast iron exhaust manifolds. Of course, headers really help...but I'm not sure I agree with the power being killed above 4500 rpm's. There are lots of folks running that cam in various stock class cars that haul the mail quite nicely.

As for your concern about a 'slippery convertor'...you get what you pay for. The B & M stuff is entry level at best [imho]...as I mentioned, call ATI, give them your information and they will get you the right convertor. We have a 3,000 rpm 'Streetmaster' behind a fairly well built big block in a 68 Nova and it performs excellent. Around town or cruising it behaves very well...give it the gas and it does the job!

www.atiracing.com

-wilma

[aaronkl84corvett]

Yes. I just ordered a converter from cliff ruggles. I trust it will be top notch

Power isnt killed at 4500 rpm, but it doesnt feel like the motor easily revs under load at and above that rpm. Could just be that the heavy car x 3.31 gears and restrictive exhaust are holding it back too much.

Once I get the new converter in, ill re-evaluate but ill probably go with 3.73s

If that doesnt really wake it up. Ill consider a slighlty smaller cam more suitable to my combo!

Cheers

[earntaz]

Originally Posted by WILMASBOYL78

I would think a 3.55 - 3.73 range with a quality convertor 2600-2800 would do the trick. You might want to check with ATI and give them your specs and possible rear gears and see what they recommend. Another thing to consider is the transmission...is it bone stock? shift kit? performance governor?...

The original L78/LS6 packages had a HD TH400, 6 lug convertor and a special governor that allowed for high rpm shifts...around 6200 rpm.

If the rpm's don't scare you, then 4.10's will really make it jump.

-wilma

If you put the 4:10 gear in it -- it will really haul donkey ... good luck!! TAZ

[aaronkl84corvett]

ok - well do you uys tend to believe that the L78/L72/LS6 etc. cam is the end all be all street-strip cam for a 10:1 BBC?

i'd happily consider a cam swap to something a little more favorable to a heavy car with taller gears - but i'm not interested in a crazy roller setup or one of those super aggressive ramp profile grinds that all the cam companies want to sell

cheers

[luzl78]

A truck torque pulling cam would work great. Eric (vintage muscle parts) can set you up well.