Need new heads! Any suggestions?

[superstroke17]

I'm working on a car now that has Systemax heads. It is smoking and most of U know the story on the systemax heads. They make good power but IMO they're junk. What aluminum heads do you prefer that can keep me in the ballpark on power without breaking the bank. Not sure of all the mods on the car, just that it has the systemax topend kit, 70 mm tb, bbk CAI, it's a 306, don't know what cam the one from the kit wasn't used but the one in it has a vey choppy idle and makes great power. I talked the owner into getting new heads cause we'll go through this again next year if he fixes the holley heads, But anyway all sugestions are greatly appreciated.

 

[Fett]

What's the issue with those heads? I ask because maybe you can sell them to offset the cost of a new set of heads.

 

[derrick gil]

AFR's

I'm having a 331 stroker built for my 89GT and i've heard from several different people that Airflow Research is definitely the way to go. They say that they are about the best you can get for a ford. Give them a look.

 

[mazroth]

I would take off the holley heads, and have them completely gone over, new parts with a port job, they would be nice heads. Cheaper this way anyway.

Or, get a set of afr/trickflow heads and go with them, but you really need to know the specs on that cam to know what springs to use on the new heads. Also, I would be certain the holley lower matches up well to the heads also if you got new ones.

 

[superstroke17]

Ive also heard good things about the AFR heads. Probably the way we'll go. The problem is that Holley designed the heads with a 17 degree valve angle. I guess to increase the flow, which causes it to eat away at the valve guides. I believe stock heads have a 20 degree angle. I think don't hold me to the #s but you get the idea. They say that at around 10k miles the guides should be replaced. I cant complain about the power, but having them redone every year is rediculous. The motor/heads only have about 12k on them. IMO it's a better idea to spend the money on a new set of trick flows or afrs than redo them over and over again. But they do make good power!! Maybe a good strip head! Just picture the different valve angle and how the rocker kinda pushes the valve sideways into the guides. Thats the problem. It causes it to burn about a quart of oil every 200 miles.

 

[mazroth]

Didnt know they burned that much oil up. Get ahold of Ed at FTI, I know back in the day he ported a set for someone, that guy runs mid 11s, but he may be able to tell you if you should replace them. He is also the guy to talk to about afr heads. I really like my afr165s on my 306.

 

[irish]

Canfields, AFRs, either way you need to know the cam specs. I'd fix the holleys and sell them but thats just me.

Matt

 

[5spd GT]

I am an AFR fan. I have had good success with them and Ed.

You may want to consider the 185cc set, if you have aftermarket pistons, and not stock style valve reliefs in your 306.

Otherwise, the 165cc is just fine.

 

[vtecwho]

Its late and I dont want to read though all the posts, sorry if this was said: AFRs have proven time and time again with a halfway decent cam to produce close to 300HP. They are expensive but WELL worth it....Just ask me!

 

[vtecwho]

BTW does anyone have any dyno #s with their AFRs on a 302 or 306.

I wish I did.

 

[Rick 91GT]

Are the Holleys the stud mount or the ped mount version? They are actually a very decent head, I'd take them over any of the Motorsport heads except the Z's, any E-brocks or knock offs. I can fix the heads if you go that route, otherwise a AFR is the way to go. Ed can give you some background on the Holleys as well....

I had the Holley kit, Lightly ported, cleaned up my old 8:8:1 comp 302 went 11.7 @ 117mph all motor @ 3275lbs, would have went .40's with the proper gear.

The 17 degree has nothing do to with the wearing out of the guides.....

 

[mazroth]

BTW does anyone have any dyno #s with their AFRs on a 302 or 306.

I wish I did.

At the wheels, Ive seen numbers as low as 280hp/300tq, you have to match the combo, or you can miss out. I have seen alot in the 330hp/350tq range. My numbers are in my sig, if corrected to sae, it should be about 333hp/386tq.

 

[strtrcr50]

I believe you can fix the systemax problems with proper length pushrods and the correct rocker arms. I thought I read that somewhere.

 

[Blown331LX]

AFR and Canfield heads are really nice but they are so damn expensive. Im currently running the new Patriot Performance Heads and they kick ass. Im running a F303 cam, Vic Jr intake and Carter 650, with a dozen of other mods and my car will scoot. I dont have ACTUAL wheel dyno numbers but I do own the desk top dyno software and plugged in my specs and got about 435 HP / 443 TQ to the flywheel. The software is suppose to be within a proven 3% accuracey to the flywheel. If so not bad for a stock bottom end and no power adders. My brand new set cost me $800 shipped to my door and came with studs and guide plates. I highly recommend them given the performance vs cost.

 

[2000xp8]

Take the heads to a good machine shop and have them re-done.

 

[Grn92LX]

Take the heads to a good machine shop and have them re-done.

Agreed

 

[EDC]

Holley heads have a history of valvetrain related issues that were actually due the typical "bolt on" mentality the marketing people pushed onto the public. Both the 20* and the 17* heads were quite strong power producers, when close attention to valvetrain geometry was performed.

I've built up a few sets of both versions of these heads and the results were very real and very good. There's a set being finished here for an NMCA Mean Street engine, that "unported", give most of the other heads in the class, a run for their money.

As for rebuilding them... yes, it is an option... however, depending on their condition, sometimes it's best to start from scratch and buy new. Especially if you need to replace everything from the guides to the seats. It's all in your budget and how hell-bent you are on keeping the Holleys. I can get you some info if you Email me directly.

One thing to be certain, buy only the best heads you can. There are plenty of examples of "cheap" heads costing a lot more money to correct/fix than a new set of AFR or TFS heads.

Here's a quick thread/note on those cheap heads. Patriot Heads Draw your own conclusions.

Ed

 

[superstroke17]

Thanks guys. I'm still not sure what we are gonna do yet. I'm taking everyones opinions very seriuosly. I personally like the heads and like the power they make, i just dont know how to fix the problem for good. Does anyone know the #s for pushrod sizes, etc. that u should use with these heads. The motor was professionally built, but there is a chance that he used the wrong stuff. Your help is greatly appreciated.

 

[2000xp8]

Pushrods are purchased by measured length, a generic size isn't worth the risk.

 

[5spd GT]

Thanks guys. I'm still not sure what we are gonna do yet. I'm taking everyones opinions very seriuosly. I personally like the heads and like the power they make, i just dont know how to fix the problem for good. Does anyone know the #s for pushrod sizes, etc. that u should use with these heads. The motor was professionally built, but there is a chance that he used the wrong stuff. Your help is greatly appreciated.

Two professionals have given their opinion.

Post # 11 is Rick, and post # 17 is Ed Curtis.

I would take their "opinion" with my or another person's opinion.