i was woundering if i could run a set of afr 185s on a 289 until i am ready to build a 331? will these hurt my power too much? or would they still do me some good. I know this might seem like a dumb question but i was not sure if it hurt the low end if they are to large or what. any advice would be nice
afr 185s
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bikefreak600
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you have to cut valve reliefs into the pistons, afr185 are the perfect head for small ci sbf with conservative hydrulic cam profile, 400-425 hp with streetable cam, 470+ with radical profile hyd roller but expect valve float at high rpm ( not good). upgrade to a solid roller and 500 is easily achieved
bikefreak600
Member
You first need to look at the chamber volumes of the 185's. If they're 64 cc's then you're going to loose at least a point in compression. Your stock heads are 54 cc. With 58 cc 185's, you'll loose all most a half point. You also need to factor in the cam you have as well and how it's going to affect the total build with the heads. And last, is the short block stock, or has it been rebuilt and with what pistons ?
as long as the valves are no bigger than 1.94in/1.60ex, and the valve lift is kept below .500" there shouldnt be a clearance issue, but i agree you need to check to be sure.
well crap that kinda sucks, but i was thinking maybe i will just take my grand that i have and turn my 289 into a 331 or a 347 for now and go for the heads when i save the money up again. i really wish i could buy them but from what it sounds like and the fact that they are actually 72 cc heads i would have to big of a risk and lose too much compression. So maybe i run a 331 or a 347 with the stock heads for a lil while. I can probably run it with my cam and such as its all aftermarket like my intake and just upgrade now. Im gunna go research which is better and such. Thanks guys!
bikefreak600
Member
if you bottom end needs work take care of that first, buy a rotating assy. then buy heads later. or you could take your shortblock to a reputable shop and have then cut your pistons. if you bottom end is strong this would be a cheap alternative. but i would go with stroker kit first, just make sure pistons have big valve reliefs cut into them. whoever you buy it from should know how big valves you can use. then go from there. and spend $ on a main support w/ arp studs. protect your investment.
Here's a solution: Go with the AFR165's. They have both a 58 cc chamber (the 185's also come in both 58 & 72) and 1.90" intake valves, so you won't have worries with piston to valve contact with your stock 289 pistons. And later with a 331 bottom end, you'll still have enough flow to make great power. This is basically the same combo I have in my 331, the Canfield heads I chose are the equals to the 165's. I'm running a 10.4 to 1 comp ratio, Ford Z303 cam, 1.7 rockers and it's all fed by a factory repop 3x2 intake/Holley carb setup. I would though mill the heads about .030 to keep the comp ratio up. When & if you do the 331, you can choose pistons to match the smaller chambers.
Hack
15 Year Member
Or just wait and do it once, do it right. The 185s are better than 165s on a 302 (with the correct build); they'll be a LOT better on a 331 or 347 if the rest of the parts are matched up correctly.
If a valve won't clear a piston with stock eyebrows and 2.02, it won't clear with 1.90's. Even if you loose compression with the heads, you will still pick up overall. If you yo 58 now, the CR will be low. But a stroker and 14cc dish later will get you where you want to be. You aren't too far away right ? I can notch them here.
It's funny you're the only one who thinks 1.9's don't clear stock pistons. You might want to let all the manufacturers know this.
Even funnier, I do it for a living and have seen it. Saying 165 will fit without knowing what the cam is, is just as foolish as saying that a .630 cam won't fit, but a .540 will, when you don't know the valve timing of either cam. Your going to get people into trouble just telling them stuff will fit, just because it has a smaller valve. I'm not going to tell a manufacturer anything. They will tell you to still check the valves. Besides, they just want to sell heads. "Will clear pistons up to .600 lift without notching the pistons." Isn't that how it goes from TW ? Funny thing is, the piston is two and a half miles from the intake valve at full lift. So why would they tell you that ? The lift has NOTHING to do with clearing pistons. And valve size does matter. But a 2.02 may not clear, and a 1.90 juuuust might fit. But it's still too close. If a 2.02 will BARELY clear or hit, you shrink the valve by .12 to get a 1.90, you move if from the piston .006. That's a far cry from the standard .030 clearance recommended. One over rev and by by valves.
bikefreak600
Member
that goes with most all aftermarket parts, its rule of thumb to check all clearances during assembly. im sure it says it on the packaging/ instructions too.
Where did you see me tell him the 165's would fit with any cam ?
Jumping to conclusions here aren't you bud ? .
And where did I recommend anything with TW heads ? You're once again making ASSumptions here as you have in the past. 
And .030 clearance is still cutting it close. And you're preaching to the choir here with lectures about cam timing being more important than total lift. I have NEVER based any recommendations as to the cam profile based on total lift alone. Where did you see me tell him the 165's would fit with any cam ?
D.Hearne said:
Looks to me right there you stated the smaller valve would fit. Yet you don't know the cam, or cam timing.
I just installed a cam I guarantee will smack stock pistons with a 1.90 valve. But I guess I could throw on a set of 165's because of the smaller valve, and it'll fit right ?And where did I recommend anything with TW heads ? You're once again making ASSumptions here as you have in the past.
FFS. Just go back and read it again until you understand before you post. I never said YOU said anything about TW heads. I said they will tell you anything to sell their product. (THEY(not you, them, got that ?))make claims to cams fitting based on lift, not cam timing)This was my point. Saying a cam will fit based on lift or valve is not a guarantee, and wrong. Once again you quote me and make an ass out of your self.
That was my point smart guy. If 2.02 will barely hit the valve pocket, and you go to a 1.90 valve, it only moves the vale in .006. So now with a smaller valve, that you recommended, it still doesn't have the required clearance. See my point here ? The smaller valve does not mean it WILL not hit. Which is what you claimed.It gains a little depth, but that's rarely a problem, ever.
Do me a favor and just act like I don't exist. Keep your stupid little snide comments and bad tech to your self before you cost someone some serious money. Can't wait until the day someone comes on here saying they dropped a valve trying to rev a 302 to 7500 with a B cam and dropped a valve trying.Get your tach checked. There's some good sound advice for ya. I'm done wasting my time with you.
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