[jays90foxbody]

Hey guys I wanna do a head swap on my 90 GT with a N/A 306. Car is my DD I'm running a trick flow street heat intake a comp cam XE266hr cam and 1.7 roller rockers. I was considering either Trick flow or AFRs. What size chambers should I be looking at for a nice low end powerband? Any other advice? Greatly appreciated

[jays90foxbody]

Sorry but if my PTV clearance is fine now will I have to worry about that changing with aftermarket heads? Thanks again

[horsepowerjunkie]

I'm running the Comp XE266hr cam in a stock 89 short block with Twisted Wedge 170 heads, the car runs outstanding. Awsome combo of cam & heads IMO. I'd probably go down to 1.6 rockers, 1.7's put the lift @ .578/.590! I had no PTV clearance issues with mine, but you should check anyway!

[jays90foxbody]

That was one of the selections I was looking at. Hows ur bottom end torque? I see ur running 3.73 I'm running 3.55 so you probably already have more bottom end then I will

[ryanw]

stock combustion chamber is 61-62cc so if you want to stay with 9 to 1 compression then buy the head with the 61-62 chamber size

[jays90foxbody]

I believe the trick flow heads utilize the 61 cc chamber. How will this benefit my setup? Or is that just to keep it steetable?

[fogged306]

As far as the actual chamber size, it won't do much of anything for performance, it's only a touch smaller than the stock ones so the small bump in compression it will create will be negligible. It's the chamber shape and port shape that are what makes the difference. On a TW head, the intake valve is rotated more towards the center and is at less of an angle so you can run a 2.02 intake valve and not have to notch your pistons for a lot of cams. 20* SBF heads like AFR ect. with a 2.02 intake valve will require you to notch the piston to get the valve to fit and they do shroud the valve some on a smaller bore because the outer side of the valve is closer to the cylinder wall than on a TW head.

You can always mill the heads down some if you want some more compression, but if you want to run pump gas, you'll have to keep it around 11:1 or so depending on your cam. You also may need to notch the pistons at that point even with a TFS head, and sometimes when you mill the heads, the intake needs to be milled as well to seat right, depending on how much you take off the head. I would do some more research if I were you and make an informed decision at a later point rather than an impulse one now on the advice of a forum or two.

[FastStang91Lx]

WTF Fogged.... we can't let people think for themselves around here, lolololol

[fogged306]

I gave up. It's a losing battle, lol.

[horsepowerjunkie]

Originally Posted by jays90foxbody That was one of the selections I was looking at. Hows ur bottom end torque? I see ur running 3.73 I'm running 3.55 so you probably already have more bottom end then I will

Low end torque is outstanding! I run a MT 255-60-15 Drag Radial on the street and still have trouble leaving from a standing start without lots of tire spin!

[jays90foxbody]

Sounds like the trick flow utilizes a better valve setup but are still out flowed by the AFRs? Trick flow also sound more bolt and go as far as modifying what I already have. I am running notched forged pistons in my block so I hope not to run into any PTV clearance issues.

[fogged306]

Don't be fooled by flow numbers, sometimes they're done on a 4.125" bore where you wouldn't have valve shrouding issues. Not saying AFR isn't a good head because they're an excellent head, but of the two I would go with a TW in a small bore i.e. less than 4.125

You may also want to look into TW highports. Really depends on your goals and budget, but those are very good heads as well. They do require specific headers though.

[jays90foxbody]

Horsepowerjunkie sounds good lots of violent neck snapping action is what I'm looking for what if any tuneing did you have done after installing ur setup? What size injectors are you running?

[horsepowerjunkie]

Originally Posted by jays90foxbody Horsepowerjunkie sounds good lots of violent neck snapping action is what I'm looking for what if any tuneing did you have done after installing ur setup? What size injectors are you running?

Mine is actually in my 82 Capri RS with a Edelbrock Performer RPM air gap intake & 650 Quick Fuel carb, so you should actually make more low end torque with a long runner EFI intake. You should be safe with 24 lbs injectors or you could go with 30's also. Once you get your combo completed you may want to consider getting chip burnt/dyno session to get the most out of your combo! Or if you're a do it yourselfer you may want to consider the Moates Quarter Horse for tuning!

[jays90foxbody]

It just seems like AFRs been made to be the holy Grail of heads and nothing flows better than them. Would highports sacrifice a little on the bottom end? I would like to be able to reuse my current headers and keep the budget reasonable.

[horsepowerjunkie]

Originally Posted by jays90foxbody It just seems like AFRs been made to be the holy Grail of heads and nothing flows better than them. Would highports sacrifice a little on the bottom end? I would like to be able to reuse my current headers and keep the budget reasonable.

IMO, Highports are way overkill for what you're doing, plus you will need different headers for them. There is nothing wrong with AFR heads, they work great. I've had a couple sets myself. My stepson has a set of AFR 165's on his stock bottom end 90LX with Trick Flow stage 1 cam and it runs awsome. I sold a 331 to my bro-in-law with AFR 185's w/ Comp XE274HR cam, and that also runs awsome, so in my opinion AFR heads are top notch, I just personally like the Twisted Wedge better. I'm positive you will be happy with the Trick Flow or AFR whichever you choose!

[69fastback]

Flow numbers mean very little, but FWIW AFRs don't outflow TWs. A TW185 flows about the same as an AFR 205. as fogged mentioned, the TWs are a better head on a stock bore block. The TWs have many advantages over a conventional head, like the AFR.

A lot of times you can run the TW head without having to notch the piston, but an inline head with a 2.02 valve will require you to notch it. Lift actually has very little to do with the piston to valve clearance. Duration is the biggest factor.

[jays90foxbody]

Yea I was thinking the highports would flow a little much for my N/A motor. I'm running JBA shorties right now will the TF heads allow me to reuse them?

Horsepowerjunkie: do you have any HP numbers off of the trick flow 170 and comp cam setup?

[69fastback]

Yes, you can use the same headers.

[jays90foxbody]

I would like to avoid notching my pistons if at all possible. But if clearance has more to do with duration then if I keep my current cam selection I shouldn't have to worry about that?