humiliategravity

Hey everyone,

I'm trying to work out my shopping list for a replacement engine for my 73 L48. I'm leaning towards a 383 with Vortec heads, Comp Cam, and good air flow components. I suspect that this will put out about 350 HP with 425 ft-lbs torque. However, I'm concerned that the higher engine power will warrant a lower gear ratio... I'm running a 3.36:1 now, and if anything I feel like it zips through the gears too quickly, even with my little 190 HP L48.

This is for street use, and I'd like to strike a reasonable balance between fuel consumption and acceleration. I'm on a budget, but should I change the ratio? How is the best way to accomplish this? New ring & pinion set?

Thanks all!

Dave

jrzvette

I think a 3.36:1 waas pretty much the standared rear with the big blocks of the mid to late 60's. When you say a lower ratio, I assume you mean lower numerically like a 2.53:1, not something like a 4.11.

You're best bet is to leave the rear alone for now (since your on a budget anyway) and see how it is with the new engine. You can always change rears later.

Glensgages

Generally, the 'long-arm' of the 383 SBC creates massive amounts of down-low torque; it should be able to 'pull' those relatively high (mechanical) gears for good acceleration.

The resulting feeling that "my little L-48 zips thru the gears too quickly" could be because the wimpy camshaft runs outta steam by 5000 RPM (?);
with a stout cam & "good air flow components", 6000 RPM isn't out of the question.

5000 RPM, with a stick & 27" tall tires (255/60R15) in Fourth Gear 'should-be' approx 120+ MPH;
60 MPH should-be approx 2500 RPM.

You may wanna leave the gear-ratio alone and 'see' how it runs; you can always change it afterwards...


[Modified by Glensgages, 4:38 PM 7/6/2004]

isosceles

I went from a 3.70 to a 3.36 and LOVE it. I think it's a good compromise for street driving with monthly visits to the track.

humiliategravity

Thanks for the input guys. Isosceles - what kind of HP/torque are you running with the 3.36?

Dave