Truck, propane 427 motor
 

My father calls me today and ask If I want a FREE complete Chevrolet "427 tonawanda" engine out of a 88-90 GMC/Chevy TopKick Propane delivery truck. The motor ran on propane. He said the motor is huge, might be a tall deck 427. It was pulled due to a spun bearing, replaced under factory warrenty. It has been sitting in a bin since 93'.

I was thinking: a rebuild and scrap the top end for Hi-Po parts.
What do ya'll think about this? Can this be re-built to be a kick ass 427 ??
Or are there diffrences from car 7.0's? Stroker maybe????

Ok well I picked up the 427 today here are the numbers:
block:10237299
heads:10101140
MK VI
H-4
http://i81.photobucket.com/albums/j2...g/CIMG0058.jpg
http://i81.photobucket.com/albums/j2...g/CIMG0061.jpg
http://i81.photobucket.com/albums/j2...g/CIMG0062.jpg
http://i81.photobucket.com/albums/j2...g/CIMG0063.jpg

Can anyone tell me if there is advantage or disadvantage having this Mark VI motor? I'm not an expert on Big Blocks. This is my first.

Bbc
 

I'd bet it has a small bore and a long stroke. It would certainly be worth pulling the heads for a look inside. That tall deck may make it hard to fit in your Camaro, but the price was right. I saw one of those at a swap meet in Arlington and almost bought it, but like you I didn't know enough about it to jump in. You got a bit of a better deal than I would have.

Actally those are a good block for a cheap builder yours is a mix year with the 6 bolt cover and non roller, you can use a older style gen 4 roller cam in it just buy a new stock timing chain cover for a gen 5 (not 4 it wont fit pan rail) bolt it on with the 6 that you have 2 you will have to open up in the cover a bit and just drill and tap the other holes to 1/4-20 in the block, you dont have to use retro fit tall lifters you can just use gen 4 roller lifters You can now buy 1 pc stroker cranks for the same price but if you get a used stroker crank for 2pc seal just use a rear main seal adaptor about 40 bucks, I have taken the later gen 4 and 5 truck blocks to 4.500 no problem you can build a cheap 2xlong rod 540 or 572 no problem it is a 4 bolt block as well good builder on a budget have fun with it :thumbsup: o yea dont even think about putting gen 4 heads on it water water water, if you actually build it and need cheap heads I still have about 20 sets of gen 5 rectangle port gm heads :thumbsup:

interesting
 

What's the bore size? Can you get any aftermartket heads for them.

Thanks 3kidsnotime! I will keep your heads in mind!

They are 4.25 bore (same as 454) std they have a 3.76 stroke same as (396) any bbc crank other than the new 8.1 will work in it if is a 2pc seal crank you need a seal adaptor longer stoke cranks will need block clearance, most after market heads today will fit gen 4 5 6 blocks the coolant passage is much larger on the 5&6 So the aftermarket heads have added materal to cover them putting a stock head from a gen 4 to a 5 or 6 will not do it, The block is a 10.2 deck height versus a 9.8 hence tall deck, originally the design was for the 4 ring piston used in the oem industrial design, but are great for long stroke long rod combo, you can go 4.5 oversize on most of the newer ones but I suggest you sonic test it first, also the machine shop that takes out .250 bore needs to do it in cycles and let the block cool its like watching paint dry.... have fun good luck