how big of cubic inches?
peanut ports may work...
special head gasket needed with 049/781 units to prevent internal water leak into lifter valley..
test fitting of heads required to block, [before reworking]>

 

The gasket you are referring to is a Fel Pro 1037. You still need to check to see there is enough surface to seal the upper water jackets. Most aftermarket heads will fit without issue. L29 Vortec heads will fit with no issues, and have a smaller 99cc chamber, they are more suited to low and mid range torque than high end HP.

 

Thanks for the part number.

 

Brian,
Like Vince said, how many cubes ? I have done a couple of 502 Mercruiser engines with the stock cast iron rectangular port heads that made over 600HP on pump gas with a .620 or so hydraulic roller.

Do you already have an engine ?

 

I got 2 sets of the 934 Sq. Port heads and I think they are great. You do need to do a little bowl clean up and a decent valve job on them but they will make power. If you have the money to spend then you can go aftermarket aluminum heads which flow much better but you pay for it also. Any GM Sq. Port head should make 600hp pretty easy. I do not think you can put 781 049 heads on a gen V engine.

 

I do not think you can put 781 049 heads on a gen V engine.

I agree. Everyone says you can with the right gaskets etc etc etc but I have yet to see a set that actually worked without leaking.

 

I'd get a different block.

 

Well if we're confirmed that the early heads will not work, looks like I'll look into an aftermarket head.

Thanks for the info folks!

 

Do not overlook the factory Vortec head, they do flow better than the peanut port heads and it is possible to make 600 HP on peanut ports!

 

Stock for stock the L29's flow better but when both are ported the peanut ports have the advantage. Just Ask Vortecpro about that.

 

Check machine shops in your area, GM made some Gen 5/6 semi-closed chambers very similar to the old -063/-215 heads. They'll definitely make some steam but will need larger valves. Compression will be about 9:1, should be safe.