[PAUL K]

Originally Posted by Jay S

I am late to the party, but here are some comments regarding the LS and Pontiac comparison. To me the performance Gap between the Pontiac based designs and the LS engine is slowing being reeled in. Turbo or N/A. Just comparing a ls 6 liter to a 400 is not using a Pontiacs attributes very well, with the same cam and cid the LS will handily beat the Pontiac. But the Pontiac has about a 1 inch taller deck than a std LS engine. Unless it is some sort of cid restrict class racing, use the CID to your advantages. Especially on a NA engine.

Here is on good example. Richard Guido out of Alberta canada runs a 515 cid turbo gto, he drives to and in Hot Rod drag week. Sometimes the trip is 2000 miles one way. I do not remember the exact mpg he average. But if I recall it was around 21-23 mpg. Unleashed IRC, it is capable of a lot of hp. Each year he seems to find more.

https://m.facebook.com/1320Videos/po...56578262167112

For a long long time I assumed big cid automatically meant gas guzzler. I no longer think that. Maybe there is a price for being big in town. Out on the open road we get in the low 20s mpg with 500+ Cid cars, no EFI, no overdrive.

Pontiac never had a MPFI system. That is one big reason you can go to a junkyard and pick up a LS in good shape, versus the Pontiac at the same miles is shot. I have a Yukon XL 6 liter about to 340,000 miles, still chugging along. They are great engines. I understand why people do the low dollar swaps. I consider doing a 6.0 swap in my 71 Chevelle, until I saw a LS in someone’s GTO years back. There is just something about classic muscle cars that the LS swap misses the mark. Put it in your 3rd gen firebird, fox body, street rod or pickup. LS is cool.. I put a 455 Olds in it years go for the same reason people do LS swaps now. Low budget, use what I have or can find.

FWIW, I have gotten right at 29.7 highway 200 mile round trip with a 5.9 Cummins in a 4x4 2003 extended cab pickup. It has about as many miles as my Yukon. Yukon best ever mpg is 16.5. 97 dodge dually 5 speed w/Cummins fuel up to about the same hp 350 or so gets 15-17mpg. 97 dodge has been one tough truck. My wifes magnum r/t awd with a hopped up 5.7 hemi gets low 20s. About the same as my 69 charger 510 cid with 3.23s.

Great post but I think things have been derailed. We're now on the "who has the best tow vehicle" part ...but I'm seeing things the same way you are.