It was dropping off at 6200, the customer didn't want to run it higher. It may have been lifter pump up, the preload was about 3/4 turn. I thought about putting heavy duty c-clips in the lifters and running less preload but we didn't have the time.

The drop off might have been the engine going out of tune as far as intake/cam/headers it might have been an RPM they didn't like. I think that is more likely as it sounded good, no misfiring. We have run the stock Magnum lifters at higher RPM on the IMCA V-6.

The dual plane Performer RPM seems to be more prone "going in and out of tune" when compared to a single plane. I had an M-1 ready to test but again didn't have the time.

What has been you experience with an upper RPM limit with the stock hydraulic roller lifters?

I built a 360 that used them and the gm 3100 valvesprings and it pulls real hard to 6000 and it just stops right there. His problem however could be the street dominator intake and smallish cam. He does also have the mopar 1.7 rockers. Again no backfiring or missing it just won't rev any more

I'm going to try beehive springs on the next one.

What springs were you running on this motor?

What's the engine going into Jesse? Will it be heading for Oahe for a 1/4 pass?

542 CTQ peak @ 4300 RPM.......nice!

was that an upsweep or downsweep test and at how many rpm's per minute.
it looks like a nice combo.

I saw an unmodified set of the Engine Quest Magnums on a 2bbl circle track Modified tour engine Thursday. Pulled 444 tq at 5400 on a 2BBl 360. I didnt see the print out for the hp, but the heads were basically stock with a good valve job.

Let us know how this motor drives in the car on 91 octane or whatever fuel the customer uses please, I'm wondering about the compression ratio and the iron head compatability. What altitude are you dynoing at? I'm impress with the results, good choice on parts and build.

Springs - Hughes 1111

Engines going in a Duster.

1/4 pass I don't know, maybe Minot, ND

Downsweep at around 250 rpm/min, but this is a Stuska with inertia correction so the numbers should be close to steady state numbers and should also match upsweep numbers. That is how the inertia correction value is set; do both an upsweep and downsweep and adjust until the numbers match. In addition the slower the sweep rate - the smaller the inertia correction. The numbers could be a little higher than what a SF upsweep would be.

There have been some huge discussions on Speedtalk on the subject of inertia correction.

It is about 2000 ft here.

The 91 octane gas we used was the last five gallons in the station's tank - probably about the worst 91 octane you would ever find.

Since this is a 80-90% street engine I did a fair amount of "cruise" testing on the dyno with the vacuum advance hooked up. The engine is set to 2500-3000 rpm and about 100-150 ft lbs and run to check cruise condition A/F ratio (LM-1) and egts.

With the total advance + vacuum advance set to about 45 I didn't hear any knocking. At 55 total+ vacuum it seemed there was some light knocking.

It will be interesting to see how it runs in the car, unhooking the vacuum advance is always an option.

Jesse,
Call me if you can. I would like to talk to you about this dyno test.
Kevin @ Hughes Engines

Jesse, how much would a pair of those heads cost setup that way?

Hey Jesse very nice numbers, mind me asking why or whats your reason for the different ratio's on the intake and exhaust rockers and do you think a different carb would of changed the result. Thanks

Jesse

Jesse, that's a sweet combination. No reason for it to not have good longevity on top of the great numbers. And, with that torque........just think of them poor unsuspecting mustangs out there.
You can take a bow for that one!

I have had both on my bench at the same time. They are very similar but ave a few differances.

The RHS has a slightly better intake port while the EQ has a slightly better exhaust.

The rhs has more room to port but I doubt any one would use more than the EQ any how.

The RHS head looks like it would flow a little better on the wet flow bench, the area behind the valve guide came up to a point instead of the flat area behind it like the factory head and the EQ. The pushrod pinch also had a slightly better radius to it.

The Valve job looked better on the RHS, the seat came all the way to the edge of the valve 1.92 and the EQ could have had a 1.88 valve in it, that is easily fixed though. The EQ had a better exhaust port and real nice radiused seat.

In a mild combo you wouldn't notice much differance in the two and a full boogy ported deal would be about the same, but someone trying to make max power with a unported head would be a little better off with the RHS but they are really more similar than they are different. The RHS is best Than the EQ than Stock but the EQ is definately closer to the RHS than the stock mag

Great Results

I'd like to see what a larger (than 2 3/4") collector might have done, I suspect it might have spread the torque and peaked it a little higher AND give you a few more ponies upstairs. Nice combo, it'll be a lot of fun to drive!

Actually a lot could have been done to make bigger numbers if that was the objective - I had a modified M-1 intake to try but no time, and yes the headers were small. The reason for that though was the customer was going to run full exhaust and 2 3/4 collectors was closer to what the in car senario would be.

Good info on the differences between the RHS and the EQ. The RHS is wider at the pushrod crossection of the intake port pair. That means the intake port window at the pushrod pinch can be larger on the RHS. I was trying to get RHS to cast a version of this head with machined pushrod holes which would open up the option of machining them wider for use with offset intake rockers. But it's like Ross Perot said of GM, "It is easier to get an elephant to tap dance than get a big company to make a change."