[tjZ28]

I'm under the impression you can legally swap a LS1 and the accompanying T56 into an older ('93-'97) 4th Gen Fbody for ESP. So, assuming that is correct what do you think would be the better combo?

* LT4 built to the limits of ESP rules + the '93 Trans gearing

or

* LS1 built to the limits of ESP rules + '98+ Trans gearing?

Let's assume this is in a '97 Hardtop Z28 built to the full limit of ESP rules also. The car generally would run on a large, fast, smooth, ultra-grippy concrete lot. BUT it would hopefully see Nationals in the next 2-3 years so it'd need to work on smaller, slippery surfaces too.

Running the numbers on 2nd gear only (since that’s where the car will spend at least 90% of it’s AutoX time) the ’93 Trans gearing would give about a 14% increase in RPM vs. the ‘94+. For example, if the ‘94+ gearing would have you at 3,000 RPM the ’93 would have you at 3,420 RPM.

I think it’s safe to say that the LT4 can match the LS1 on torque/hp until maybe 4500 or 5000 RPM. Only losing out a bit right up to ~6200-6300. But can a LS1 make as much torque/hp at 3,000 RPM as a LT4 could at 3,420 RPM?

Thoughts?

-TJ

PS- Yes, my head hurts too.

This post has been edited by tjZ28: Jul 11 2007, 12:53 AM

[LT4Firehawk]

LT4 is 4 bolt, and GM had the oil leak issue pretty well resolved by the time the LT4s came out. Also, the optispark is not an issue after 95.

With proper tuning, my LT4 Hawk makes 311RWHP, which peaks at 5800rpm, and only drops to about 295 at 6200. By comparison, my stock 2000 TA made 304RWHP peaking at 5400, and dropping to 290 at 6200. TQ on the LT4 is ~326 and flat as a table until 4700. The LS1 made peak TQ of 317, peaking at 4000, but was started at only about 290. You can check out dnyo graphs of all my previous cars (LT1s, LS1, LS6, LT4 at My Website

Having owned both an LS1 f-body, and an LT4 f-body, I would definitely go with the LT4, especially if you're going with the 93 tranny.