C4 Question

[Stu]

My buddy just recently got a '91 Vette 6-speed and we were wondering a bit about it. Does anyone know much about these? I told him I thought it had an L98 Engine but after looking at it it looked alot like an Lt1. So I'm not to sure what he's got and I'm an F-body guy so I don't know too much about the C4 vettes. Any info on like Engine/Tranny/Hp/Tq would greatly help.

[Patman]

The 91 came with the 250hp L98 motor, unless someone swapped it out for an LT1. The two motors look totally different, the L98 has the exposed intake runners on it while the LT1 intake is totally flat.

Here is an L98:

http://hp-car.com/engine/chevy/images/350JPG.JPG

Here is an LT1:

http://corvetteactioncenter.com/specs/1996/images/lt1.gif

[Stu]

Hey thanks for the info I'll let him know it does look more like an Lt1 though but to his knowledge it hasn't been swapped

[Patman]

Originally posted by Stu
Hey thanks for the info I'll let him know it does look more like an Lt1 though but to his knowledge it hasn't been swapped

Then his car must be a 92, because no 91s came with the LT1. 1992 was the first year for the LT1.

[digitalcorvettes]

The LT1 did not come out until 1992.

You sure it's a '91 ? Even if that car needed a new motor, it'd make more sense to stick with an L98 and just re-use your accessories... converting to an LT1 is a little odd... but it has been done.

If they guy wanted more HP, there are plenty-o-things you can do to bring an L98 to street-killer status.:D

[Stu]

Well I checked it out again and it's an L98. It's bone stock and we just had it dynoed on Sat and he's got 216 Rwhp and 319 Rwtq. I had no Idea they were torque monsters. HE'd like to bump his hp a little more though.

[Patman]

216rwhp? Yikes! I thought L98s were higher than this. A buddy of mine has an 88 Convertible that ran a 13.9 bone stock. It's automatic too.

[Stu]

Well if he has the kind of Torque my buddy has that is probably why. He is scared to take his to the track but If I can get ahold of it one night I'll take it:D

[BET IT]

great car to mod, one of the best!:cool: :D

[Stu]

Yea from what I've found out they take mods really well

[HZ900]

If you want to get the horsepower up without losing much of the low end torque then I would suggest a super-ram intake(TPIS miniram is better IMO but you will loose some torque on the low end), long tube headers, and a free flowing exhaust. The heads on the 90-91 were called D-port heads and are quite good, especially if you p&p them.

The problem with the TPI setup on these cars is that the intake is the biggest restriction on the motor, it really falls on its face after about 4800 rpm because it can't flow the air to breathe at higher rpms. The intake was originally designed for the 305 ci motor but they found if they put it on the 350 they could get alot of torque out of it, which makes it a great autoX car.

If you look at the 60' and 1/8th mile times for these cars you will see they are comparable with stock lt1/ls1's, and with a few mods even better, but after that without changing/modifying the intake they have a hard time.

[Stu]

Hey man thanks for the input, that was very informative. We were trying to figure out why they went to an Lt1 from the L98 if the torque was that great.