IIRC- you used to be able to get 0.080" pistons for the 427.

It's expensive but the block can also be sleeved.

No siamesed 427 has ever existed but a 427 tall deck "truck block"(65-76 #3855961) other sizes for the tall deck was 366, 396 or 454.

Sure you can get but if a block needs to be sleeved or bored over 060 its gone,,,there just isnīt enough wall thickness to be safe.

GM Built a tall deck 427 "Truck" block in the 70s that was 1/4 inch taller because the pistons had a 4th oil control ring installed for less oil consumption this engine should have a gear driven cam from the factory. Mercruiser used this engine for thier 325-350 HP inboards. Engine shops found this block useful to create some of the early stroker engines

any chance you know of a way of checking to see if this is what i have? it has a suffix code of marine and kiekhaefer marine. it was definately does not have a truck code or casting #. anyone know how tall a standard deck 427 should measure?

Thanks to everyone who has input into this discussion.

Look at the front of the block where the water pump mounts. If the top of the ovals are touching the deck, it's standard height. If there's an additional 1/4" it's a tall deck.

We've sleeved alcohol and nitro motors with no problems. An under-400hp BBC won't present a problem, reliavbility-wise. The real issue is if there's some collecibility. If it were an original motor from a numbers-matching vintage musclecar, then it certainly would be worth the effort and expense. I haven't seen a huge collector's market for 70's boats but one exists for the old-timers. This motor might be worth a bundle 30 years from now.

I've got one of those 961 blocks laying around if someone needs it...

JH

A std. deck height BBC is 9.8" and a tall deck is 10.2". This is measured frome the crankshaft center line. Most TD 427 blocks will take a +.125 over bore. The only way to know for sure is to sonic test the block. Custom pistons can be made in any size. Check with JE, Ross, Arias, Wiseco, etc., they can help.

Nitro motors are usually Aluminum blocks...at least those Iīve grown accustomed to...
There sure ainīt no problems on a quartermile and sleeving is a good way to repair a block if itīs not cracked or rusted thru anywhere else. Iīve sleeved blocks plenty but those have been 1000c.i. Truck Diesels...
And yes Iīwouldnīt throw that block just away but usefullness of it is limited as it is. It has more value as a display engine IMO if nothing else then Eye appeal and sentimental...