Brenden Schaeffer

I have a 1992 C4 corvette stock LT1 internals. I have an intake, headers, and bigger throttle body. I would really like to make it faster with out breaking the bank. What would you guys recommend. Iv been looking at cams and am quite confused about them. I know how to do the swap, just don’t know what the lift and duration means, and what u can do with out having to spend 1500$ on heads. I’m not looking for a 500HP NA monster. But something that packs a punch. Iv looked at forums and browsed the internet but I want to do as much as I can for as cheap as I can( I have the money but only want to spend so much). What would you do? Is there a cam that comes with everything to do it wth out buying many other parts. Gearing? Heads? Tune? Lifters? Let me know what you guys think and what you would do.
Thanks

GREGGPENN

What kind of intake and headers. I don't think the TB is going to get you much....especially on a budget build. If you can resell it, consider adding what you get to your budget. You didn't mention if it was an auto or stick? What gearing is out back?

Brenden Schaeffer

Kevova

Gear change would be a big help 2.59 is terrible unless you on the highway a lot. Hot Cam Kit would be a pretty standard cam change and a new PROM (programming for cam ) shouldn't be a major deal. It depend on how much DIY you can handle with your budget. A used 3.73 D36 assembly and 1.6 roller rockers should fit in you budget with money left over. That would make it quite peppy, engine will be turning around 2500 rpm @ 75 mph with stock tires.

Tom400CFI

If it were my car, I'd do gears first, then a cam after if I felt it still needed more.

vader86

I would go with gears first, then a new higher stall TC. That will increase your feeling of power.

3.54s or 3.73s would be fine, and though some will recommend a 2600 stall TC or higher for an LT1 car, I would personally go lower, 2200-2400, because of how they feel when youre driving around town.

You need to get a ring & pinion, you don't have to buy a whole new D36 or D44, and have it installed by a good shop. You will want to buy gears for the 2-series D36 case. Any transmission shop can swap out a TC.

Do those things and see how you like it, changing cams requires some thought and goals in mind, but you will want to have had these two things done already then anyway, so do these first.

Brenden Schaeffer

ok sweet thank you guys I’ll look into doing that stuff and get prices and let you all know!

ddahlgren

Changing to the 3.06 is like adding 60 ft.lbs. to the engine. It would take more money and time to do that compared to the gear change. I assume there is a speedo gear change to go with it too.

ddahlgren

What is the stock stall speed? 1800?

Brenden Schaeffer

aguilar92c4

find a manual car and swap the whole rear end, most of them come with 354 gears. A ring and pinion install will run you over $500 plus in just labor alone at a shop. Its not really something you can do yourself unless you know how to properly set up a rear end and you will need a press and the proper tools, gauges,etc. As far as a cam goes, You want to keep the duration low, this is a computer controlled vehicle and even with a tune it will be hard to get right if the cam is not within a certain spec. You want to keep LSA above 112 also when choosing a camshaft for this vehicle.

GREGGPENN

ddahlgren was pointing out the mechanical change in torque to the rear wheels. The rear end ratio is a direct multiplier of torque. Higher ratios produce more torque. (Essentially, you run with lower gear ratios.)

(330/2.59) * 3.06 = 390...which is a gain of 60ft/lbs of TQ -- on an engine dyno.

Typically though...rear wheel numbers are about 85% of engine dyno numbers (due to drive train losses). 330*.85=280rwtq
(280/2.59) * 3.73 = 403rwtq

So, if you converted to 3.73 gearing, it would FEEL like you had a 120ft/lb bump in torque....(in 3rd where the gear ratio is 1).

Another way to think of it though....is you'll have a super-low 1st gear, 2nd will react more like 1st, 3rd more like 2nd, and 4th would feel like 3rd. And, actually, I think you'd be running higher in rpms in 4th than you are in 3rd now. That's probably why ddahlgren suggested 3.06 gears because it's not so extreme. It's definitely why he pointed out your speedo would be way off unless you changed the speedo gear.

If you consider a gear change, query/search for feedback before choosing your gear ratio. I'm fairly certain you can find whatever ratio you'd want....not just 3.73s.

Brenden Schaeffer

GREGGPENN

Automatics came with the smaller Dana 36 differential. If you decide to do other mods (increase power) down the road, that's why a swap to a Dana 44 is a good idea. It was mentioned by aguilar92c4 above.

He is correct is pointing out ZF6 cars come with the larger rear end. If you choose JUST to do the gears, "performance" automatics mostly came with the 3.54 gears. Still D36 AFAIF though.

I never memorized the RPO codes because mine came with D44 3.33 ZF6...so I've never really considered a gear swap for my car.

vader86

You mean Dana 36 differential, not 33. He has a D36 with a 2-series case.

GREGGPENN

Ooops! Thanks!

mtwoolford

I can almost guarantee the lobes on the cam will show wear, and maybe a lot of wear. Google it, these cam lobes are often worn with corresponding damage to the roller in the lifter body; I'd check the cam and lifters first and if suspect, I'd choose a cam and lifter combo and work out from there.

psychodiagnostik

I have a 1993 with 3.73s as the only mod, going from 2.59. It TOTALLY transformed the car. Not only will it jump off the line from a stop, it's more responsive in most other driving situations. It does use more gas but who cares, the 2.59s got great mileage but with those factory gears the car accelerated like it was towing a horse trailer compared to the 3.73s.