AFR165cc
.100 NA
.200 123/118
.300 186/153
.400 225/178
.500 243/185
.550 246/191
.600 NA

TFTW 170cc
.100 63/53
.200 141/107
.300 205/144
.400 233/171
.500 251/187
.550 NA
.600 251/193

In comparing these more closely, these have slightly different intake and exhaust runner sizes I(165cc/170cc) E(68cc/63cc). AFR has larger exhaust runners (flows better) and TFTW has larger intake runners (flows better). Regardless of the valve placement, it appears from these numbers that the runner size is mostly responsible for the difference in flow numbers. That being said, I think I would choose the TFTW heads for most street applications and maybe put larger exhaust lifts on them to help with the output.

I remember reading about issues with running larger lift cams or long duration cams, but that has been years ago. Seems like IIRC, overlap in your cam or lift in the .5 range created valve to piston clearance issues with the smaller small block Fords. Am I right?

 

Haven't heard anything either way on that, or why the exhaust doesn't flow quite as well.

I'd hesitate to buy AFR heads though, from what I've been hearing lately about their quality (weren't you the one that trashed a set of valves?). Supposedly their flow rates are slightly exaggerated as well. If I was going to spend that much money, I think I'd start looking at the new Edelbrock CNC heads.

 

Starfury, I did trash my AFR valves, but I would not have had an issue if I had built out the heads with my own valves or installed lash caps to begin with. Yes AFR valves are crap, but I am still very happy with their performance, if not their valve quality. Not promoting AFR or downing Trick Flow. Trick Flow makes some nice stuff, but please look into the valve clearance thing b/c I think it is an issue due to the "twisted" valve location. I like Edelbrock's numbers on their RPM XT heads but they are too big for a 289. IMO, the smaller Edelbrock stuff is third or forth down the list with relation to performance.

The Edelbrock RPM heads in the 170cc 60cc combustion chamber version flow:
.100 72/75
.200 132/104
.300 183/142
.400 216/159
.500 245/170
.600 249/174

This is for the 1.90 intake valve. The 2.02 version flow very slightly better above .400 lift. Neither version really keeps up compared to AFR or Trick Flow in the same head class on the intake side and they get killed on the exhaust side. They are still much better than stock , but you can do better if you want to.

Kalli, get you a set of nice Trick Flows, but please check on the valve to piston clearance.

 

Have you tried looking in your exhaust ports in your heads or in your exhaust manifold ports to see if you a different looking port. with how much water you are talking about you might have steam cleaned a chamber and can possibly identify your bad cylinder.

 

that's an idea. but one way or another I have to pull them anyway.
Girlfriend agrees with Tad. says briong em to the shop to have them tested. might be a shame to spend huge money on heads I wouldn't have needed. friend called engine shop and they want 60 quid each head for pressure testing and another 60 for skimming. i see the fun side of aftermarket heads and wanted them all along. that's why i'm struggling to put any money on head checking.

As for AFR/TFS I'm pretty much settled on the TFS. I'm sure the AFRs are bombing output monsters on high revs but my stock conrod bolts are afraid to go near 5500. Me included. As I have currently a stock cam and I hope I don't have to change that at the moment it will stay that way for a good long time. From what I see in dyno results the two heads are next to each other with that cam or a future xe262 under 5500. At the same time the 200quid difference in the heads (1200 vs 1400) speaks for the TFS.

You're right with the 2.02 valves. on a 289 stocker that's a no go, but the TFS have a modified valve angle to allow it. even their documentation claims that with small block valvetrain there's no need to even go as far as checking clearance (although I'll do that for the sake of it shouldmI ever buy).
The only thing that lets me tend to the AFRs at the moment is that I could get them as 58cc application which seems to make more low end torque and responsiveness. TFS are 61cc. I was lookign at a NiB AFR165cc on eBay that I could have snatched but they were 61cc as well and seller couldn't get them over for under 500. that's why i didn't do it.

the big question is still. go to engine shop and check and then buy or go to engine shop and check and repair or just buy ... my wallet says no way but other parts say go for it ...

oh and i have decided against Edl 60229. they are a no go for my application. but thats my personal opinion and my desktop dyno talking


I'll let you all know

Kalli

 

with the heads off you should be able to see which chamber is different (cracked) even if you can't see the crack (which you should). i'd give them a good visual inspection before you go spending any money on anything.

 

i'm off on Saturday. I'm gonna pull the whole lot and go from there

 

Buy a coolant pressurizing tool before throwing good money away. Pull the plugs and pressurize the system and see if you have coolant leaks. They'll show themselves by bleeding off pressure. Do it with a full cooling system. then slowly turn motor over by hand and look for coolant pouring out. that is you bad cylinder. Pull that head, have it check on the correct cylinder. Look for crack in the cylinder wall also. Definitely sounds like a compression leak though.

 

Oh yeah, a dead give away may be a brand new looking plug on one cylinder if it's firing it enough to steam the plug.

 

cpr:
maybe if I'd buy one of those radiator lids with a airhose connector on top. Friend where I usually do all my repairs has a compressor. that should do.
i guess I could just remove all spark plugs, pressurize the radiator and then manually crank my engine and see if it flows out of my spark plug holes eventually. or at least droplets

does that sound like a plan?
or is there a device that i could buy especially for this with a manual pump attached or something?

Kalli