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Promaxx heads and Valako

Old 11-07-2021, 05:22 PM
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Default Promaxx heads and Valako

Jim has done an awesome job on my heads. A very reduced sized intake ports and flowing near 415 cfm at .600 and 450 cfm at .700 lift. Gotta love old school head porters that outflow CNC heads. The air speed is insane on these. All out of a 317 head. Just wanted to give jim a thumbs up.
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05-18-2022, 03:39 PM
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Just a little update. We ran into P/V clearance issues with the bigger valves so had to disassemble short blocks and fly cut the pistons. Back on track but about two months behind schedule. Now ready for the dyno tune.



Old 11-08-2021, 10:19 AM
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I am very interested in the lower lift numbers, can you post those as well?
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Old 11-08-2021, 11:14 AM
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Originally Posted by ThisIsLivin View Post
I am very interested in the lower lift numbers, can you post those as well?
.200/178
.300/243
.400/317
.500/370
.600/413
.650/439
.700/450
.800/463

port is 1.750 x 2.250
cams are SR 255-259/704-704 net

This has been in the works for some time now with delays on my end “with builds” til now. Jim’s just been working on these on and off during spare time however making improvements along the way.

I am confirming cfm @ .300 this afternoon.
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Old 11-08-2021, 04:50 PM
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Those are mighty impressive numbers. How good is the exhaust side.
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Old 11-09-2021, 07:47 AM
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Those are really good numbers especially for the port size. What size is the intake valve? I would be a little concerned about the velocity, you have to be on the edge of going sonic.
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Old 11-09-2021, 08:18 AM
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Pretty certain 2.300. He wanted 2.350 however I was a little concerned with piston clearance. Short blocks assembled and anxiously waiting. NA builds.



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Old 11-09-2021, 12:32 PM
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amazing numbers on top, whats really surprising (on top of the outstanding high lift numbers) is whatever work jimmy V did to get them there did not hurt low lift flow which I would expect on something that gains so much on top. Cant hardly wait to see the outcome on the dyno. How big are your new motors, whats compression going to be, Smitty
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Old 11-09-2021, 12:48 PM
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Those billet timing covers are sweet
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Old 11-09-2021, 12:55 PM
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Tks guys - their 565, 4.25 stroke, dart blks, 10.5:1. He’s got my Brodix hv 2001 intakes and 1150 two circuit carbs but Jim’s pretty adamant about claying up a profiler sniper intake and seeing what he can do with it. I kinda always thought with the same amount of porting etc the gains would be minimal btwn several of them.

If I see 700 plus “anything” at More Power Racing’s dyno I’d be happy. Just want a good tune and reliable engines. Since they did all my machining, balancing etc I had them do the assemblies since everything was there.

I always got a kick out of that engine I believe you dyno’d smitty with the chinamen intake and out performed others. 😂
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Old 11-09-2021, 03:35 PM
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Originally Posted by getrdunn View Post
Tks guys - their 565, 4.25 stroke, dart blks, 10.5:1. He’s got my Brodix hv 2001 intakes and 1150 two circuit carbs but Jim’s pretty adamant about claying up a profiler sniper intake and seeing what he can do with it. I kinda always thought with the same amount of porting etc the gains would be minimal btwn several of them.

If I see 700 plus “anything” at More Power Racing’s dyno I’d be happy. Just want a good tune and reliable engines. Since they did all my machining, balancing etc I had them do the assemblies since everything was there.

I always got a kick out of that engine I believe you dyno’d smitty with the chinamen intake and out performed others. 😂
yeah, i pulled that 548 about 100 times trying various intakes, efi and carbs na , made outstanding hp on top (707) at 6300, 6400 if i rember right but what it didnt make was tq which was in the 620 area. But, keep in mind it was a 8.4-1 blower motor with good flowing heads, giant cam but no blower. I've dynoed alot of engines since then, glad to see you putting some compression in these, I've dynoed quite a few engines others built with 8.8, 9-1 w open plenum intakes, high flowing heads that made less tq than smaller engines with modded mpi intakes and performer rpm intakes!
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