GM motors

[gtx28]

I had a few questions I thought that i could get answers for on here. I have seen that there are several diff versions of the 427ci motor, in the modern vettes.

There are the sleeved, or bored out motors like the darton sleeves out on the market, then also there are the factory c5r blocks. Well ive seen that block available in cast iron, but is it also available from gm in aluminum?

Also i was looking to find out what is the largest safe displacement for the ls1/ls6 aluminum motors? I have heard rumors of a 455ci project based off the gen3 motor. But have not seen any completed projects.

[T-Bird]

actually newer vette's have 350's NOT 427's

[RC45]

Well, actually 346 ci ;)

There are the sleeved, or bored out motors like the darton sleeves out on the market, then also there are the factory c5r blocks. Well ive seen that block available in cast iron, but is it also available from gm in aluminum?


What block is cast iron?

The LS1, LS6 and C5R are aluminium blocks. The lac4 and LQ9 are the iron blocks, that can be punched to 408ci - quite a couple of Z06's and Coupes I know of with iron block 400's running 200+ shots of nitrous.

Even with the Darton sleeves 436ci is pushing - however, there have been a few attempts to run a 454ci with the LS6 block resleeved and bored.

The only such project I know of, has run into heat soak issues - and the between bore walls being a little thin for comfort - even with the Darton sleeves.

But where there is a will - there is a way - so someone will do it... ;)

[SilverPhoenix]

There was that Hot Rod mag with the article on the monster LS1

[gtx28]

actually newer vette's have 350's NOT 427's

I was never refering to factory motors. All the cars i was refering to are the modified, ls1 346ci as rc had mentioned.

Rc, on one of the gm performance directorys, they had a supposed c5r block for sale it was a 427ci, all iron block. Mabey it was not the correct specs, but I was just curious, the block was for sale at $3999.

Any links on those larger displacement genIII motors would be appreciated.

[graywolf624]

on one of the gm performance directorys, they had a supposed c5r block for sale it was a 427ci, all iron block

The c5-r block is all alluminum. Heck.. the last 350 gm built non crate that was iron was the lt1. The ls1 in the camaros are even alluminum(albeit iron heads as opposed to the alluminum heads in the ls6)