Questions about Big Block Chevy Tall Deck Engines

[Gwyn Reedy]

The latest GM high performance catalog shows 502 cu in blocks with
'standard' deck height of 9.80 inches and tall deck blocks with a deck
height of 10.20 inches. .0400 difference. Can't be sure that is what was
done on the earlier models, but seems likely.

Book also has all the forged steel cranks.

Knowing what I do now from all these helpful responses, if my 427 block is
ruined and the crank broken, I can put a 502 tall deck block in there.
Problem will be in getting the correct pistons to give a suitable
compression ratio. I probably should go for the 4 rings too, if they can be
had for that monster bore.

Project is a 70 Chevy 2 1/2  ton car hauler. It has a 5 speed transmission,
2 speed rear end and now has a 350 in it.  I've located an original 427
truck with the cold air induction hood, and the 427 engine with all
brackets. Also have in-dash air conditioning from a 70 pickup which will fit
with modest reworking. Truck already has super paint, upholstery and chrome.
Looking for a 3 foot sleeper cab to bolt on.

Truck replaces a 71 truck of the same size which has major rust problems.
That truck has a 4 speed. It gets by quite well with the 350 2-barrel even
with GVW of 25-30,000. But those extra 75 cu in (or 150 extra with the 502)
and the 4 barrel Holley, and the closer ratios of the 5 speed are likely to
help a lot on those long uphill grades.

Thanks to all the people who have contributed information in response to my
query. It has been so helpful and all was done in one weekend.

Gwyn Reedy
Brandon, Florida
mailto:mgr at mgrcorp.com

-----Original Message-----
From: owner-diy_efi at efi332.eng.ohio-state.edu
[mailto:owner-diy_efi at efi332.eng.ohio-state.edu]On Behalf Of Jim Davies
Sent: Saturday, November 07, 1998 11:53 PM
To: diy_efi at efi332.eng.ohio-state.edu
Subject: Re: Questions about Big Block Chevy Tall Deck Engines




On Sat, 7 Nov 1998, Sandy wrote:

> I don't remember if the rods were longer in the Truck motors, but I know
> that they used a 4 ring pistons and that was the reason the extra height
> was needed in the deck. I don't thing the deck was 1" taller, less, but
not
> 100%.
>
IIRC, the number is 0.700" taller