Don Terrill’s Speed-Talk

Are the latest castings "out performing" the prior ones? Someone mentioned something about possible dimension changes.
useage: SportMods, 350 sbc, 2701 Edelbrock intakes, 4412 carb, 175 max compression

thanks

Yes they are. Much nicer casting. They are now the old rhs torque head IIRC. We saw about +10hp gain.

Yep, outta the box, 8-12hp across the board here as well

wheres the best place to buy them? do they have one that will bolt up to a vortec intake cleanly

CH350I is for the early intakes.

Now a bit of dilemma, mainly IMCA type rules with < 2200 lbs chassis, competition is very tight on a hp track. If you guys were already pushing the boundries and still gaining more hp with these, I think this means all currently approved production heads (487,441,993,etc.) may be starting out a little behind. Not sure if it's a game changer yet, but everything else being equal they look to run strong.

i just built a set for a wissota Midwest mod (similar to sport mod) a week ago.
they are performing noticeably better than his oem set, and the castings do indeed look nicer, but i wasn't impressed with the machine work compared to earlier ones.
i had a couple of exhaust guides that the valves (manley, not cheap junk) wouldn't even go into.
i expect to touch up valve jobs, maybe even touch up guide sizes a bit, but the fact that they were so far out that a valve wouldn't even go in is not confidence inspiring.
i like the heads, better than i though i would, so i hope this was just a little hiccup while they are trying to increase their production rates.

Just curious how much they weigh compared to a production head like a 441 or 993. If they are heavier do they make enough additional power to offset the additional nose weight?

Them heads like a 10 degree valve on the intake

DaveMcLain wrote:Just curious how much they weigh compared to a production head like a 441 or 993. If they are heavier do they make enough additional power to offset the additional nose weight?

About 50LBS

Out of curiosity what are we defining as the "latest" castings? I know there was a switch last winter, but has there been another casting switch? I know I have seen variations in the machining tolerances over the sets I have seen this year, but have not ordered any new ones in last couple months as I still had some in inventory so I'm curious if things are changing more.

the new castings are the old rhs heads and they have "imca" on only 1 end of the head vs having it on both sides.

5000 series and up

dirtracr5 wrote:Yes they are. Much nicer casting. They are now the old rhs torque head IIRC. We saw about +10hp gain.

I agree they are a nicer casting but we did not see the performance increase. I was expecting to pick up but maybe they may like a little different cam than what we where running.

anyone pour an intake runner to see how many cc's they are . what is the part # head that takes a 2101 intake with 64cc chamber.