Ted,

Thank you for running all of those tests on the different heads.  One comparison I see is the Stock G head was 5HP less and 9 ft/lbs more than a stock C1TE head?  I thought the C1TE heads would be alot worse.  I am in the process of changing out my C1TE heads for a pair of G heads on my 272.  Now I am wondering if it will make much of a difference in horse power/torque.  What do you think?

Be sure to look at that ‘Ported’ column on the chart as that separates the stock from the modified heads.  The C1TE heads were ported so they will not be a stock to stock comparison when looking at the stock 'G' heads.  The C1TE heads used in the test were prepared by Tim McMaster to demonstrate that the C1TE heads could be a viable alternative to the the harder to find ‘G’ heads when properly prepared.  On the other hand, the stock COAE heads should be comparable to stock C1TE head performance so use the stock COAE performance numbers for your stock to stock comparison.

Lorena, Texas (South of Waco)

Ted:



A question on the mule engine.

Are you using the Best gaskets and how deep is the pistons in the hole?



Just wondering when I get to installing the Mummert heads whether I need to "0" deck the engine or not as I am running steel shims now with flat tops 0.015" in the holes.



Thank you for the ton of info in the test.

marv

Lorena, Texas (South of Waco)

Another thing interesting is the wide divergence of results from the various ported "G" heads. Obviously there's a lot more to porting those heads than just hogging them out. I believe John Mummert has alluded to this fact in YBM in the past. Did he supply any of the "G" heads by chance?

Paul

Although John donated a stock set of ECZ-C heads for the test, John didn’t do any porting on them.  John only had a hand in porting the aluminum heads but none of the others.  And you’re right on the differences in the G head performances.  Valve angles, quality of the port work, valve sizes, and combustion chamber shrouding are just a few of the variables in determining how a cylinder head ultimately performs.

Lorena, Texas (South of Waco)

Charlie.  I’ll work on putting the head test in a scoring format in the near future.  I’m thinking two scoring formats where one format is 2500-3500 rpms (street driving) and then the 2500-5500 rpm format representing overall performance.  For simplicity I’ll keep the chart in the current order and not rearranged in descending or ascending order based on the scores.  The current order on the chart has the heads grouped by casting number and does tend to help when comparing heads within a group.

Lorena, Texas (South of Waco)

Ted,  in your opinion,would it be a safe performance mod. to bolt a set of the aluminum heads on a freshly rebuilt 272/292, giving that all necessary factors will be to spec, or new. and do you think that an upgrade like this would net gains comparable to those charted?. Thanks for your time. portland, oregon.

rev.johnchoppermohamedjerryleejames

hi ted, were you using 1.64 valves in the truck heads?

 lincoln/merc. y-blocks &mel's                                                               bucyrus, ohio.

The varied comparisons of the "C" & "G" heads is interesting. Ignoring various cost factors & going strickly with Teds' findings, shows stk to stk that the "G" head is noticeably superior in peak power. Up 17 h.p. & 14 lb ft over the "C" heads. When you start comparing stock, milled & or ported heads the water gets murky. Yes, "C"s can be brought fairly close by milling to 9 to 1, resulting in being just 2 h.p. & 8 lb.ft. down. Then ad porting gets them 5 h.p. up, but still 5 lb ft. down, close but all that machining & porting isn't free. And the stk "G"s still maintain the best stk torque rating. And of course the other figures indicate that if suitably modified, they have a lot more potential...

Paul