I am looking to add some hp to my 7.4 litre and i know i need to replace the heads to make any big power improvements. I know the rectangle port heads are good as well as the 049 oval port heads? Does anyone know if any of the other oval port heads are a good upgrade to the "peanut port" heads such as the 336781 heads or 846236? I don't claim to know the first thing about these casting numbers but know where i can get either of the above sets of heads cheaply.

thanks
jake

I have a set of rectangular port heads off my Gen IV 454 mag. Ported, 1.94 2.25 Iconel valves, set up for adjustable rockers, fresh valve job new Crower springs and seals. I uograded to aluminum. $1000
Bob

The GM cast iron rectangle port heads crack easily and at random....so, that is something to consider and think about before you buy them.

If interested these heads are perfect. They came off of great running motor that was due for a freshen up, I can put you in contact with the builder to verify.
Bob

Hey there Jake. Kaama has a point about the GEN IV rectangle heads, and if the 7.4 you're upgrading is orig, then it's a GENIV. The GENV rect heads were imrpoved with more metal and greater cooling.
If you are only doing the heads, the rects are good for a 7.4 but the ovals are the way to go. Good Luck!!

i have a pair of 049s empty mint castings let me know if thats what your going to do

i'm running 781's on my engine , they are identical to the 049's , which i also have a pair of if you need some
they need a trip to the machine shop , i think one valve is bent , and should get a basic rebuild

so the 781 heads are a large oval port head? like i said, i know nothing about these casting numbers

These are ready to bolt on. ARP bolts and all. Send me a PM or an E-Mail to send pics. For some reason they are not downloading to this thread.
Bob

You can view in classifieds ad #22911
Bob