....Impending rain I'd think makes for some "bad" air

I don't have any modern tight lash cams to check, so I don't not how they compare.

My Engle was a 55 year old design and was 6.55 degrees difference

The data I have from 45 years ago from helping someone else on a 302 Z28 stocker with a Lunati cam is 5.19 degrees difference. (Lash Called for 0.010" Intake and 0.012" Exhaust)

Stan

My RAIV headed 400 though with an UD 288/296 HP peak was 6100.

For most solid cams Mike Jones uses a .012 ramp, resulting in less 'difference' between hyd and solid. Most Ultradyne solids used a .017 ramp.

Below two images labelled 'twelve' and 'seventeen' for different solid ramps, my 12 numbers are within 1 degree of Mike's, he likely used a different rod/stroke ratio. Mine are symmetrical lobes.

hi tc you send me a private message regarding my 428 if i find i new cam...

sadly had no time to finish my 428 with th 60919 cam...

what makes me wonder that you lost 5 mph changing to 60919 cam..

this is a lot...i think ...maybe there are unnown changes...compression lost ...carb change. ignition timing...

Read post 17.....

Is there any value in 1 3/4" headers?

I was wondering the same thing as I think 1 5/8" headers are counter productive above 4800 rpm.
The inlet to the header tube needs to be atleast 1/16" of a inch larger all the way around the perimeter of the Exh port flange!

I have the 60311 on my list for the other 428, guess I'll take it off.

I did not know that we lose .030 lift with hyd lifters.

The longer duration idea is why I put the 60919 in.

I should have just posted iron heads as I opened up the chambers on these 670's

My worn lobe SFT cam was 110 LSA. I'd like a better idle, so I thought I'd try 112 or 113. I was hoping I'd get some et's from others as this cam is talked about a lot.

I will next time out!

Yeah, hit rain when I arrived at the track 1&1/2 hour drive. Sat for an hour, cleared up enough for two test runs, then started raining again.

Hope to figure that out too.

"My worn lobe SFT cam was 110 LSA. I'd like a better idle, so I thought I'd try 112 or 113. I was hoping I'd get some et's from others as this cam is talked about a lot."

"Rough" idle is simply a by-product of tight LSA. You either have to raise the compression ratio or wider LSA to offset the overlap, "reversion" and lost efficiency at idle speed, just the laws of physic with these things.

Tuning plays a HUGE roll in idle quality when using pretty decent size tight LSA camshafts in these engines. They are going to want/like/need more timing at idle and more fuel to the mixture screws to make them happy.

Recently had a 350 SBC build come in here that idled poorly but made great power off idle. The owner/builder had consulted with me on cam selection and I recommended the GM LT4 "Hot" cam for it, on a 112LSA. He called Comp and they sent their version of that cam to him on a 110LSA. He was using trick flow aluminum heads but only 9.7 to 1 compression so it didn't idle all that well, but made somewhere around 435hp and pretty stout torque numbers for a little 350 SBC build.

I spent about half an hour with the carburetor increasing idle bypass air and putting more fuel to the mixture screws. Night and day difference in idle quality when we put the carb back in place. It tamed the cam pretty good and reduced the "stinky" exhaust from being a tad too lean.......Cliff

My point was go bigger than a RAIV type cam.

Crower lists the peak HP RPM as 4800 with the 919.

The VooDoo HFT 705 is like one step up (241/249), and you could get it cut on a 112 if you wanted. But with your gears, you could get away with bigger. True your SCR may impact it some, but the recommendations are very 'centered' between iron and aluminum heads.

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A 4.250 stroke engine with 260 cfm heads, Performer RPM intake, large Q-jet and headers made peak power at 5300 rpm on the dyno with the 60919 cam. I would presume a shorter stroke would have a higher peak rpm.


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The OP here said 670 ported, curious who did the work and are the numbers up there also?

Would be nice if Crower was precise with their numbers, seems to be much confusion where their ADV rating is..

Way back in 2004 with my old 455 and Crower 60919 cam we made peak HP at 5600rpm's with the new (at that time) KRE heads.

4,400 539.4 451.9
4,500 537.4 460.4
4,600 534.9 468.5
4,700 532.5 476.5
4,800 523.5 478.5
4,900 518.9 484.1
5,000 511.4 486.9
5,100 501.6 487.1
5,200 492.7 487.8
5,300 485.4 489.8
5,400 478.1 491.6
5,500 471.9 494.2
5,600 463.6 494.3

I wouldn't change the recipe, just the procedure and conditions your cooking with/in firstly.

On the next 428, something like this may work. Can some of you respond to the idea mentioned before that the HFT cam loses .030 lift because of the H lifters?

I did, at .300 lift 200/140, .500 lift 250/180

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Correct.
Driving around town, I felt that the car accelerated very well. I was impressed!
This thread was because I was expecting some great 1/4 mile numbers. The night before I ran the 1/4 mile, (results in my first post ) I ran on a different track that is 1/8 mile. Even with slight tire spin the car ran
60 ft 1.656
1/8 et 7.731

Being a parent, I should have followed my own rule. If you don't expect anything, you won't be disappointed.

"Can some of you respond to the idea mentioned before that the HFT cam loses .030 lift because of the H lifters?"

Related:

https://forums.maxperformanceinc.com...intron+testing


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Post 24, per Mike Jones. He would have discovered long ago if there was a necessary hyd plunger compensation factor required.
Some lift is lost due to deflection.

"Some lift is lost due to deflection"

Deflection ? As in the one example of pushrod flex ?



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Pushrod is one.

Others

Rocker arm Deflection
Rocker Stud Deflection
Cam Core Diameter

https://www.enginelabs.com/engine-te...st-valve-lift/