Hi,

What is the gear ratio in overdrive with the 4 +3 setup? I am assuming fourth gear is 1:1 when not in overdrive, correct?

Thanks,
vettebob

4th is 1:1 as you guess.

OD (in 4th) is .68

4th is 1:1 as you guess.OD (in 4th) is .68
There were two O/d ratios
MH5: 0.62
MK2: 0.68 apparently came in Z51 cars

Huh. Good to know.

huh. Good to know.

i knew there were two different od ratios, but i didn't know what they were, this sounds correct. Many years use a 3.07:1 diff ratio.

Race on!!!

Many years use a 3.07:1 diff ratio.
3.07 was the only ratio with 4+3 except in your '84 where there was rare ( 3.31? ) option available as well

3.07 was the only ratio with 4+3 except in your '84 where there was rare ( 3.31? ) option available as well
correct. The 3.07 was the standard equipment ratio in all 1984 corvettes, regardless of which transmission the car had. The optional 3.31 gears were only installed in 210 1984 corvettes. The 3.31:1 gears were a 1984 only offering. It fit only the dana d36 diff which were in all 1984s manual or automatic. Later the d44 used in manual transmission cars, after 1984 was available with 3.33:1 gears; a different rear end and a different ratio.

Race on!!!

Thanks for the info guys.

Does anyone happen to know the camshaft specs, lift, duration, and lobe centers, for the 1987 Vette engine??

VETTEBOB

Does anyone happen to know the camshaft specs, lift, duration, and lobe centers, for the 1987 Vette engine??
Wimpy comes to mind

Cam 87 L98 #14093643
@.050" 202'/206'
Lift (w/1.5) .403"/.415" LSA 114.5

Yep, pretty wimpy....

Does anyone know how much lift you can use on a 1987 L-98 before having piston/valve clearance issues??

Thanks,
VETTEBOB

Wimpy comes to mind

Cam 87 L98 #14093643
@.050" 202'/206'
Lift (w/1.5) .403"/.415" LSA 114.5

Wimpy is one way of looking at it!