My intake is casting # 3919803.  I guess that is a 1968 327 intake.  My engine casting # is 3970010.  That could be a 327 or 350.  Is there any way to tell for sure if it is a 350 or a 327?  Also, if it is a 350, does running a 327 intake cause problems?  I have a massive vacume leak under the carb and need to change the gaskets, is there anything special I should consider?  Hope to have this baby humming soon, right now it barks like a pit bull, but runs like a 15 year old mule.

Casting # 3970010 is for a 350, '69-80. A 327 would be # 3914678. (or # 3914660, but this # has not been verified as being used in 'Vettes)
You've got a 350, but the intake will work fine. Not much difference in the intakes on small blocks, anyway.
Intake cast # 3919803 is correct for '68 300 & 350hp 327.

Does the engine have any stamped numbers/letters on the block, just ahead of the pass side head? That would tell you exactly what it is, & what it was originally installed in.

StreetShark,

Intake# 3919803 = 1968 Cast Iron Intake Manifold 300 & 350 HP

Block Casting# 3970010 = 1970 350ci Block (300, 350, & 370 HP) and the 1971 350 Block (270 & 330 HP)

As for compatability, it's my understanding that there should be no compatability problems with this combo, as they are both small blocks.

I would feel better about the compatability if someone offered a second opinion.

Good luck,

Anthony

The intakes will interchange with no problem.

Thanks, the block has been decked, the VIN machined off.  At least I know more today than yesterday, thanks all.  I have to replace the carb mounting gasket, should fix my vacume leak.   Guess it is just dried out and cracked from so many years of being in that barn.