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Nice Alex. That thing was a beast for sure. Why the SR 23's? Are the 20's not legal or a weight adder???
20s are not legal and if they were they would be ran on a spread port weight and not conventional. People were saying they were 20's and I was teched at the track 2 weekends ago and proved that they were 23's
 

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If more than .800" lift I agree on .903". Trying to plan a decent bolt together agenda. You don't really find Dart blocks stocked anywhere with .903" lifters. Dart wants a month to do it and recommends bushed lifters for oil control with the thru holes getting bigger with bore increase. 7/16" pushrods are easy on exhaust, not so easy on intake with wide ports and no offset lifter. Not enough room on AFR CNC heads either without getting thin on intake port material. Short deck blocks used to fit some GM stock engine bays with off the shelf headers. Raised cam blocks are more money to the combo too.
We order and run Dart blocks with .903's and no bushings. Never had an issue. The passenger side lifter galley needs to be plugged at the back, in front of the distributor hole, especially with hyd. rollers. I would upgrade to a .903 long before .800". Pretty much any solid roller will benefit. AFR's and 7/16 push rids...never had a problem there either. Some guys just put heads on a mill and move the entire pushrod hole over but if you do it by hand and only remove material where the pushrod is hitting, you won't break through the port. You're not going to throw something like this together in 8 wks. If you don't have the time to do it right, you might as well just buy a complete "shelf" engine somewhere.
 

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If more than .800" lift I agree on .903". Trying to plan a decent bolt together agenda. You don't really find Dart blocks stocked anywhere with .903" lifters. Dart wants a month to do it and recommends bushed lifters for oil control with the thru holes getting bigger with bore increase. 7/16" pushrods are easy on exhaust, not so easy on intake with wide ports and no offset lifter. Not enough room on AFR CNC heads either without getting thin on intake port material. Short deck blocks used to fit some GM stock engine bays with off the shelf headers. Raised cam blocks are more money to the combo too.
Mark,
I cleared my AFRs (the Mamo 360 version) for 7/16 pushrods. I did it carefully by hand with some blueing and a big rat tail file so only to lighty clear the areas that were absolutely needed. I was still concerned about the wall stock of the ports in a couple areas but, all is well. I should have purchased an ultrasonic thickness checker but, I took my chances.
 

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Thanks Alex. I figured as much. Haven't really followed Ultra since Butch stepped out, or NA 10.5 since Mike put it on the back burner also. So rules are where they are. BUT I am glad to see some of the rule makers seeing some of the conventional head are getting close to the spread port stuff.

Congrads on the record and good luck
 

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As for pushrods, I'm not even sure they make them in 7/16's but I would have to believe so since I have them in 1/2", but wouldn't a double taper pushrod help this clearance issue?
 

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Discussion Starter #26
All good stuff on the combo.

Back to original question. 24 degree factory CNC heads with 2.350" intake valve size. Which is a better?

Any one with experience with the Dart CNC 365 head?

Also noticed the Dart spec sheets for the 355 and 365 differ in intake valve length. 355 calls for +.250" extra length and 365 calls for +.350". Wonder why?
 

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I would look at Snipers? You have a bare $3500.00 budget and Speier has some tunes up 500 CFM Sniper 375 XL for $3800.00. I know it's not "factory" but that seems like a pretty interesting option!!!!
 

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What's Wrong with the AFR 377 or 385 heads..... I know people will say they're to BIG for a 540-565
but they have a big Bowl area which chews up a lot of cc.... I have them on my 532, it makes a shit ton of power
1100 to be exact, cam has .850 lift, I run it to 8400, has a shit ton of bottom end.... it has went 1.058 in sixty foot @ 2275 lbs.... 7.40 @ 183.86 mph....

2.350 valve and I have clearance them for 1/2" pushrods on the intake and exhaust, didn't break through
anywhere.
AFR 357 would take a 2.350 valve no problem...... I like there castings, and would put them right up there with Dart, Brodix, profiler...ETC....

I am also putting a set of AFR 385's on a 565 right now.... that one has .937 lifters, 55 mm camshaft and .920/.880 lift......hoping for upper 1100's hp wise, Maybe 1200's if my ducks are in a row...LOL
 

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Based on the above, what parameters would be the jumping point from Black Mambas to the larger diameter? Lift, closed/open pressure, rpm?
Black Mambas are for guys who either can't afford or aren't willing to go to the .903 for whatever reason. The better choice would be the .903 if it's at all possible. IMO when you start getting in the 280-300# seat range and you're going to see >/=7000rpm it's time for some .903's and bigger pushrods. There's really no downside to bigger lifters.
 

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What's Wrong with the AFR 377 or 385 heads..... I know people will say they're to BIG for a 540-565
but they have a big Bowl area which chews up a lot of cc.... I have them on my 532, it makes a shit ton of power
1100 to be exact, cam has .850 lift, I run it to 8400, has a shit ton of bottom end.... it has went 1.058 in sixty foot @ 2275 lbs.... 7.40 @ 183.86 mph....

2.350 valve and I have clearance them for 1/2" pushrods on the intake and exhaust, didn't break through
anywhere.
AFR 357 would take a 2.350 valve no problem...... I like there castings, and would put them right up there with Dart, Brodix, profiler...ETC....

I am also putting a set of AFR 385's on a 565 right now.... that one has .937 lifters, 55 mm camshaft and .920/.880 lift......hoping for upper 1100's hp wise, Maybe 1200's if my ducks are in a row...LOL
RCM, I've never got the "heads are too big" thing? I will agree that's some heads can be too big for certain applications, but I don't believe a head can be too big.

Now with this being a street car with some track times, I would be asking more of what he wants, KILLER ET's or better street driving to decide on heads? There have been plenty of motors UNDER 500 inches that work very well at the track with heads bigger than the AFR 357/377's, but you have to turn them some RPM's. And on a traction-limited street car, this I think helps ease it off the line, then RPM and wheel speed gets the car moving!
 

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Black Mambas are for guys who either can't afford or aren't willing to go to the .903 for whatever reason. The better choice would be the .903 if it's at all possible. IMO when you start getting in the 280-300# seat range and you're going to see >/=7000rpm it's time for some .903's and bigger pushrods. There's really no downside to bigger lifters.
Thanks Scott.
 

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I would look at Snipers? You have a bare $3500.00 budget and Speier has some tunes up 500 CFM Sniper 375 XL for $3800.00. I know it's not "factory" but that seems like a pretty interesting option!!!!
I think the sniper xl heads are bigger 400+ cc heads from what I saw when checking them out.
 

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There should be a , between the 375 and XL. There 2 different heads. It's not listed as 375XL on Chad's site. If you go there to look, there listed separately, 375 and XL.

Just mentioned it as the XL are listed at $3,800.00, $300 more than his $3,500.00 budget.
 

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There should be a , between the 375 and XL. There 2 different heads. It's not listed as 375XL on Chad's site. If you go there to look, there listed separately, 375 and XL.

Just mentioned it as the XL are listed at $3,800.00, $300 more than his $3,500.00 budget.
Gotcha. I just bought a used set of sniper x 375s that were done by reher morrison- Milled into front of heads. They have a the factory cnc port and a little work by RM. Angle milled to 23 degrees and a little hand blending.
Gonna try and get them flowed. Not sure if anybody on here had one of those sets on a bench?. RM just lists the flow #s for the factory 24 degree cnc heads I believe.
 

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Have you checked with Darin Morgan at RM, My Profiler street heads are 449 [email protected] with 2.350 valves?
No I havnt called them. These are 2.350 valves also. They are gonna go on a street/ Strip 582 build. A little overkill probably but got them for a pretty good price with the t&d shaft rockers.
 

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Gotcha. I just bought a used set of sniper x 375s that were done by reher morrison- Milled into front of heads. They have a the factory cnc port and a little work by RM. Angle milled to 23 degrees and a little hand blending.
Gonna try and get them flowed. Not sure if anybody on here had one of those sets on a bench?. RM just lists the flow #s for the factory 24 degree cnc heads I believe.
Sounds like it's going to be a decent top end if everything is in good shape. Angle milling opens a bit of a can of worms so do your homework before you get too far into the project. Make sure you mock everything up...intake, heads on the block, check head bolt hole alignment, check valve to piston pocket alignment, look at pushrod clearances and rocker geometry, check intake fit, port alignment, intake face angle, etc. Once you get flow numbers I would get with Chris Straub on the cam and valve train parts.
 

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Have you checked with Darin Morgan at RM, My Profiler street heads are 449 [email protected] with 2.350 valves?
69, Do as mike says, CALL DARIN!!! Without a doubt, one of the best in the business and since it's there stuff, use them for any parts needed. They know more about those heads and will design the cam, or sell you the cam that would be best for what THEY did to the heads and get the most out of them for YOUR intended purpose.

Remember Darin actually designed those heads as well and did the R&D in TPS too. Can't get any better knowledge then that. I spoke to Darin on a few occasions and has help with my P/S heads that came through them. He was helpful.

Good luck
 
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