Some questions about the different years

[MuRCieLaGo]

Originally Posted by Paul Workman

Agree w/ all said so far.

Here's a link to Marc Haibeck's site.

Mark performs performance upgrades to the LT5. You'll see there that where the 90-92 375 hp motors and the 93-95 motors receive the full treatment, their respective performance is equal.

One thing many don't realize too is the head bolts on the LT5 are MASSIVE, compared to a typical SBC. And, the head bolts of the 90-92 two-bolt block are larger than the individual bolts of the 4-bolt 93-95 block. And, many examples exist of 415, 427, and 441 cid displacements with 2-bolt blocks that are straddling 700 hp, NA on pump gas. Try that with a SBC!

Aside from sharing bore center dimensions, there are no interchangeable parts with the SBC, and certainly no comparison either with the LT5's rugged "bullet proof" reliability or output per cubic inch for a street driven motor.

So, I wouldn't give 2 vs. 4 bolt LT5s a second thought, especially if it is to be fully ported anyway. And, offsetting the 30 hp advantage of the 93-95 ZR-1s, is the additional weight.

Performance wise, it is pretty much a toss-up across the years in stock form.

Thanks a lot guys and thanks for your detailed answer Paul.

Would it cost much to have a '90 motor modded the exact same way that gives the '93 motor these 30 extra horsepowers? Is it doable?

Again, thanks for your patience and I really appreciate it!