how far would you bore a 427?

65 SD L79 · Canadian Poncho Superstar!

how far would you bore a 427?

4SPEED427 · A Poncho Legend!

If it needs more than .060 I would sleeve it.

Have you had it sonic checked? Some guys even say .040 and no more.

65 SD L79 · Canadian Poncho Superstar!

4SPEED427 wrote:
If it needs more than .060 I would sleeve it.
Have you had it sonic checked? Some guys even say .040 and no more.

I have not picked up block yet to have it looked at

4SPEED427 · A Poncho Legend!

I had a discussion about sleeves with the shop foreman at the machine shop a couple of years ago. I'm old school and always thought sleeves were nothing but trouble because way back when, that's how it was. He told me that sleeves are pretty much bullet proof now.

I've also heard some racers sleeve their blocks because it's better. I don't have any proof of that, and maybe there's some racers here who can give some input on that?

Canadian Poncho · A Poncho Legend!

I've seen that fellow on the Hagerty Youtube channel use sleeves on a couple of engine builds and like you said Carl they seem quite reliable.

DonSSDD · Canadian Poncho Superstar!

Lots of the 348-409 guys have them sleeved and no issues as long as the shop knows what they are doing. Most of them are racers, they also use stitched blocks that were cracked.

66 Beau · Poncho Master!

When they sleeve the 427s, do they end up cutting in to the coolant chamber/water jacket? I think the sleeves are something like .100 or .125 thick so the bore would be cut out 200 to 250 thou over (minus a bit for interference fit).
If theyre not hitting the water jacket when sleeving them, I would think you should definitely be safe at 0.060 over. Likely even more.
What pistons are available?

65 SD L79 · Canadian Poncho Superstar!

Stoped into machine shop to check on block. He sonic tested it and said even in the thinnest wall it was no problem going 80 over. Lots of meat. Block has no cracks so good to go

Howmac · Guru

66 Beau wrote:
When they sleeve the 427s, do they end up cutting in to the coolant chamber/water jacket? I think the sleeves are something like .100 or .125 thick so the bore would be cut out 200 to 250 thou over (minus a bit for interference fit).
If theyre not hitting the water jacket when sleeving them, I would think you should definitely be safe at 0.060 over. Likely even more.
What pistons are available?

I lost a 427 block due to a sleeve cutting into the water jacket . I was dealing with a block that needed to go 030 , but discovered it had a core shift from birth ( hence the sleeves on one bank ) . Of course we found out after we assembled the engine and put in the fluids. Not fun , but luckily I had another short block sitting at home and the engine builder reassembled using my other block ( under warranty ) . Later on , I took the bad block to another engine shop to see if it was salvageable . The smallest , minute hole was extremely hard to find , but it was there when we pressurized the block .