Need Great HEAD advice (509) MAG
 

Okay... So i have a 01 Baja H2x with 502 mag that has been Freshened up with srp blower pistons and scat rods. 8.50.1 Now a 509 with a ASM502 comp cam. It previously had a m1 on 6.5lbs and i would turn a 26 pitch prop about 5,250 with 4 people in boat and loaded on fuel with stock heads. Which according to my speedo (NON GPS) said about 74mph at 6,000ft elevation. I recently got bored... Sold blower bought a M3 put it on and first trip out blew head gasket with it at 5lbs. I tore motor down. Put in Pro comp 320cc aluminum heads, and a 28 pitch prop. I went out and tuned it. Boat said 70mph with two people in it and half tank fuel on 5lbs. at 4,450ft elevation Turning the new 28 pitch about 4,850rpms roughly. So i'm like hum... More boost... Order smaller pulley tune it... See 8lbs. Then i see 68mph... and about 4,750rpm... So at half throttle plained out not really building boost i see 60mph. From half to full throttle i only get 8 to 9mph lucky to see 10mph. So my thinking is that these pro comp heads suck ass... and possibly seeing valve float... I did compression check on every cylinder and i see 95lbs of pressure accross every one of em. Which is very low... I did research and heard that these heads are coming from china and have been known for quality control issues. SO here are the ones i'm thinking of getting... What do you guys think? And if anything else comes to mind or opinions i'm all ears!

http://www.adperformance.com/index.p...oducts_id=1003

I can get these same heads from my buddy who is afr dealer with hydrolic lifter springs, inconel valves and heads milled down to raise my comp. Which i'm wondering if i should do. Its 8.5 thinking of milling to raise to 9.25 because of elevation here. all for 2,300.00 bucks!

Thoughts????

Thanks!!!!

do a leak down and see why compression is so low and where its going

Yeah... I will! It's about 5 degrees here with a foot of snow on the ground now. So i don't think i'll be playing jack frost anytime soon. But after doing a lot of research i hear it's very common with these heads. My buddy ran him in his dragged out big block s-10 and had same issue... Took heads off and to machine shop had them go through em. But long store i'm sure it's not piston rings or the new mls head gaskets i put on. But i guess you never know... And the engine looked great when pulling off old heads. Like i said engine is fresh with low hrs. So anyone one running these AFR heads? Good? You think 225cc or 235cc for my build?

First you need a GPS speedo. You can even use an I phone with a speed app, I do. Second, 95 psi is low. You should be 110+. When you installed new heads did you size the pushrods corectly? It almsot sounds like you are not getting full valve lift.

AFR heads are great but before you spend $ I would try and figure out what is going on currently.

Wannabe

I'm runnin the AFR 357 cnc heads on my 572s with 8.5 comp ratio 8-71s and mild rollers they make 820hp and 900 ft. lbs all in by 5600 rpm sized correctly they make great power the 325 or 335 cnc would probably be good

make sure you upgrade to inconnel exhaust valves with forced induction, hard coating would add some insurance as well

fixx
 

1 procomp heads suck..cc them and you willsee,all the chambers are going to be off by at leaste 10 cc's..look into a set of afr's 305 heads,,also sounds like your cam is blowing all the boost out the exhaust..they like stock cams,fogducker ran a stock 385 hp cam on his 454 efi and his boat ran 87 mph,,did 67 before that..

Yeah... It's a must to have them valves in marine use. But thanks for advice on heads. I think i'm going the 2101-1 I'm sold!

Yeah... I have that app. Actually on my phone aswell. Used it to tune computer to set speedo when did gear change on my camaro. I compaired it to two other cars and it's like within 1mph. They're pretty accurate. Just never really used it on lake but was always thinking about trying it. I just might have to this summer. Also... I used a pushrod length checker before ordering push rods. That way valve geometry was on. Far as compression check. It was done with rockers off and on. It made no difference!

Really? that big a difference with cam huh. I know i guess the specs on that cam on lift is like 600 intake and 620 exhaust. But the motor in the boat had the same cam with m1 on 6.5lbs with stock head and ran faster. Then Pro comps on m3 with 8lbs. All i changed was blower and heads. But now i am curious what it would done with different cam anyway.

+1 on the 305's with CNC'd chambers, I have them on my NA 524 in a Velocity 280 and I run 90 with 4 adults and full fuel. I did do gasket match and port work myself. I f you check the flow on the fully CNC'd 315's they are better than anything from anyone else. they flow better than other's 350's with better velocity for more low end torque. I've had 9 adults and several coolers with a 30p Bravo prop and still got on plane without tabs.

Are you at sea level? I hear it makes a great deal of difference. And so you guys think with a blown 509 I should go that small and steer away from 325cc heads?

What did you do with the fuel injection to compensate for the extra boost which requires extra fuel, it sounds like the motor is very lean.

I've got 80lbs injectors A1000 fuel pump running Holley commander 950 I have wide band set at 12.1 afr

I think I'm about 800-900 ft above sea level on Northern Lake Huron. You need to look at the flow of the AFR 315's and compare them to the others, Chevy High Performance Magazine did a side by side dyno run with all the majors and the smaller AFR's out flowed and out performed all the others. If you don't believe me just talk to Bob Madera he's one of the best and he swears by the AFR 305/315's.

Fixx brings up a real important point with a blower you must consider the cam overlap and duration, what is the duration at .050, remember you want to keep the boost in the cyl. not blow it though!, the exhaust scavanging design of NA cam not as important on a blower motor, I know it ran on the M1 unit, but the M3 could be blowing the extra air right on through. Just a thought! I run 315 heads seem to flow great in my bbc.

just pickup my 509s yesterday from the machine shop, AFR 335 marine coated heads, 691 crane roller, with 3.3 whipples, dustin at whipple recomended I use them..

A Procharged engine uses a different cam than a Roots or Whipple engine.

tcwcar,

What is your max WOT RPM target with your 509?

Bob

I turn my 509 500hp cam, 5600 @6psi with a M3 thru their ****ty carb box 950 prosystems carb, 80.4 GPS 253 checkmate, no tuning as of yet...building EFI for next year...

Bob the cam is suppost to be good to 3200 to 6400 RPM dont think going I'm to spin them any harder then 6k, got your stud griddles on for AFR heads, nice pieces but need new valve covers now for clearance, one change always leads to another thing you have to deal with...:lolhit:

Thanks everyone for your insight and thoughts. I think after looking at the 315 competition series I'm pretty sold. Spendy, But worth the extra 600 bucks. They seem to out flow the 225's and will provide better low end torque numbers. So ill be ordering them in couple weeks! ;)

So I'm ordering my AFR 315 comp. Heads this week. Getting pretty excitded. I know a lot of factors are involved. But I'm curious roughly how much mph I might pick up with my combination. Anyone with similar build or guesses out there? I'm Really curious....