Bore & Stroke?

[Sizzler]

Originally Posted by 427SnakeSC

It will soon be getting down to the wire on the Keith Craft build of my 427 SO. I would like to know which bore & stroke is the best to get and why. Thanks.

Apparently originality is important to you, else why the Side-oiler (not the best design for the street) in the plastic replica.

Soooo, for originality sake, I'd go with the 4.23" bore and the 3.78" stroke.
Your only other option, to stay the course originality-wise, is a 4.13" bore with a 3.98" stroke to give you the 428 inch displacement many original cobras actually came with, though if you choose this option, you may have the wrong block?

Any more hard questions?

[427SnakeSC]

Originally Posted by Sizzler

Apparently originality is important to you, else why the Side-oiler (not the best design for the street) in the plastic replica.

Soooo, for originality sake, I'd go with the 4.23" bore and the 3.78" stroke.
Your only other option, to stay the course originality-wise, is a 4.13" bore with a 3.98" stroke to give you the 428 inch displacement many original cobras actually came with, though if you choose this option, you may have the wrong block?

Any more hard questions?

Yes, though I don't think it is a difficult question. If I go with this bore and stroke to get the 428 cu. in., is there pistons available for this? I called Keith a couple of months ago to find out if I could keep the original bore and stroke to give me the original 427 size. I'm pretty sure he told me that the pistons for 427 were very difficult to get. Correct me if I am wrong, there. If I have a choice, I would like to keep the original 427 cu. in. displacement. If not, I will probably go with the recommended 482 cu. in.

[Commander]

Originally Posted by 427SnakeSC

I'm pretty sure he told me that the pistons for 427 were very difficult to get. Correct me if I am wrong, there. If I have a choice, I would like to keep the original 427 cu. in. displacement. If not, I will probably go with the recommended 482 cu. in.

I've run into a lot of, though I'm sure there are more acceptable euphemisms out there, lying lately.

Your aftermarket block probably comes with a 4.25" bore. All he should have told you was that it's pretty much impossible for him to take a 4.25" bore back down to 4.23". Why all the subterfuge?

Honestly, if you're spending the coin on a new block, what's the cost of a set of custom pistons in the grand scheme of things? And you can specify the correct offset instead of taking none or the GM's version (4.25" is a GM size and you'll get "GM" pistons).

So it starts: a genuine "sideoiler" block (only it's an aftermarket "Pond" block that's had some design "upgrades") displacing "427" (only it was easy to bore and stroke it up to 60's Cadillac displacement using "GM" parts and new crank from China) in a genuine CSX cobra (with the modern plastic body).

I just wish people'd be more upfront and honest about things. Here's an honest truth: there's no replacement for displacement.

[Barry_R]

My current Genesis block seems to be just fine - no issues and it made 752HP at 6300 RPM at the Engine Masters deal on 91 octane. Same engine got shipped over to Kaase's for photos and it went 759HP on Jon's dyno...

The aftermarket blocks are all referenced to go to 4.25 bore. The reason is not pistons - - the guys at Diamond will make me any piston I can dream of. We've done some for FEs with blowers, and some for 300 ci inline sixes with turbos... The forgings are FE specific and not converted GM anything.

The reason is piston ring availability. Since the original moter was the only one using that 4.233 bore, standard size rings have become virtually non-existant. Chevrolet size based 4.250 rings are inexpensive and plentiful.

I cannot imagine a reason not to go "big" - but I suppose we could tweak a 391 truck forged crank offset in the "wrong direction" to put the cubes back at 427 with the slight overbore. Wierd but possible. I'd go big if it was mine.

Wait a minute - - I'm doing something a lot like that for next year's Engine Masters Challenge - - taking my 4.350 bore motor and destroking it to meet the 434 cube rules ... I guess the wierd label fits

[Burgs]

Originally Posted by Barry_R

I cannot imagine a reason not to go "big" -

I agree, let that beast take a deep breath. At least it will look right when you open thed hood.

Brad