[bigwildgrin]

okay I'll the first to admit I know very little about chevy's so be patient with me here. I'm in the process of rebuilding my 427, and I see some adds for heads and intakes that say they dont fit on tall deck blocks. what is one, whats the difference, how do I know if I have one and are they good or bad? no wonder I love pontiacs so, one block fits all... ok you chevy freaks, sock it to me. and dont spare my feelings.

[coldknock]

It's the same reason a 302 intake won't work on a 351W. The decks(where the heads bolt on) are farther away from the crankshaft centerline. Therefore the heads are spread a little farther apart due to the 90 degree V-angle of the engine.

It's just math, no rocket science.

Larry

[BigDawgsEatFirst]

340220.....427T......68-85...4-bolt
364776.....427T......68-85...4-bolt
473478.....427T......77-90...4-bolt
3782870....427T......68-76...4-bolt
3855961....427.......66......2-bolt
3869942....427.......66-67...2 or 4 bolt
3904351....427.......67......2 or 4 bolt
3916321....427.......68......2 or 4 bolt
3925521....427T......68-85...4-bolt
3935439....427.......68-69...2 or 4 bolt
3937726....427T......68-84...4-bolt
3946052....427.......69......4-bolt, Alum. ZL-1, Mark IV
3946053....427.......97......4-bolt, Alum. ZL-1, 2nd version, Mark IV
3955270....427.......69......2 or 4 bolt
3955276....427T......68-73...4-bolt
3963512....427.......69......2 or 4 bolt
3969858....427T......68-84...4-bolt
3999294....427T......68-84...4-bolt
10069284...427T..............4-bolt, Mark IV, Tall deck
10114184...427T......91-up...4-bolt, Gen.V
12550312...427T......96-up...4-bolt, Gen.VI, 4.250" bore, fuel pump boss,

T = Tall deck, 10.2" deck height

[topfuel]

Std deck height is 9.8". These blocks (396, 427, 454) were used in pass. cars and lt. trucks. Tall deck height is 10.2". These blocks (366 & 427) were used in medium duty trucks. The easiest (quickest) way to determine a tall block is to look where the water pump bolts to the block. If the deck of the block is right at the top of the water pump mounting bolt hole, it is a std. deck block. If there is approx. 3/8" between the top of the bolt hole and the deck, it is a tall deck.

I hope this helps.