after my 86 305 tpi block cracked, i switched it directly over to an 84 305 HO block and heads. i left the heads on and only switched the intake. What are the differances in the heads? is there even a differance? What change in performance will i see if any?

 

They should both be the "416" casting. Shouldn't see any difference in performance.

 

Yup, as far as I know they're the same.

 

no difference sorry bud

 

You have a great opportunity for performance improvement here. This is what you do:

Take the heads off the TPI engine and take them to a machine shop and have them check for cracks, rough in valve seats for 1.94" intake valves, check the valve guides and replace or knurl any that are worn, and remove the rocker studs and machine/tap them for screw-in. While the heads are at the shop, get a Standard Abrasives Deluxe Porting Kit, die grinder, safety goggles, ear protection muffs, and Mechanix gloves. Bring the heads home and follow the SA guidelines included in the Deluxe Kit on the heads.

Take the heads back to the machine shop along with new 1.94" intake valves, screw-in rocker studs and new valve springs. While they finish putting the heads back together with a 3-angle valve job, take the heads off the engine. Port the plenum & base, then put it all back together when you get the heads back from the machine shop. If you like, put in a nice Crane CompuCam at this time, too.

If you haven't done so yet, install headers & high-flow cat (having the heads out of the way is a great time to do this).

Doing all this, you will see an improvement by changing back to the TPI heads.