Head Help

That's a pretty nasty cam for stock heads. Combined with a single plane intake you won't have much bottom end torque. If your running a 4000 stall and pretty deep gears (3.91-4.56) you'll be ok but you need to get the flow numbers up on those heads or it won't work right with that big cam.

BTW: It's real easy to tell a X head. Just look at the area between the spark plugs and you'll see a large X cast onto the head. Also the casting number ends in 894X

Here's the stock flow numbers on my 68 340 heads.

lift-----int. cfm-------------Exh. cfm
.200-----120------------------95
.300-----167------------------131
.400-----200------------------148
.450-----209-----------------153
.500-----205------------------155
.550-----202------------------158

You'll notice I highlighted figures at .45 lift cause this is where the intake was at peak.

Here's the same heads after I ported and polished them and installed back cut swirl polished stainless valves.


lift----------int. cfm--------exh. cfm
.200---------129-------------104
.300---------188-------------135
.400---------236-------------155
.500---------243-------------165
.550--------250-------------170
.600---------239-------------174

I again highlighted the peak intake flow numbers.

I am an amateur (Have only done 4 sets of heads total) so I'm sure these numbers are nowhere close to what they can do but it gives you an idea.

If you plan on re-using the cam and intake you have IMHO you need to get the flow numbers up to at least what mine are but more preferably.