[Sunshine68]

I trying to find a cylinder head for a turbocharged setup. I know you want a lower compression ratio, but what size of intake and exhaust ports are needed. Im also confused on if the heads recommended rpm ranges are still accurate, since its will have force induction

[uedlose]

turbos don't need the heads to flow big numbers to make good power. the intake ports are always getting the air forced in and there is always gone to be a cork in the exhaust to hold back exhaust flow that is the turbo so much for the FREE HP everyone says you get it is not free the cork takes some away. I know some guys have gone 8.50s on out of the box TFS TW and that fast on 185 AFRs. RPM ranges are out the window. you will need to run a good valve spring due to the boost press. and the back-press in the headers trying to push the valves open. But port size will come into play if your are moving up in the CID. just as it would with any engine.

[ITLRUN]

If you want the right set of heads, Trick Flow makes an excellent set of heads. Not only are they a good set of heads, but they will out flow AFR's that much I know first hand. I have a set of Trick Flows on my 89 Notch, 306cu.in. engine fully forged internals and balanced rotating assembly. Match your components, the heads have been CNC ported on the intake side and ported and polished on the exhaust side, JESEL Valve Train, too many mods to actually list. But there is over 20K in the motor alone, Pro M 90MM MAF calibrated now for 36lb. injectors, 4.10 gearing 5 speed and best run so far 9.90's finally into the 9's. This Notch is also street legal, and N/A with FAST Engine Management, Aeromotive Fuel System, the list goes on etc, just do your research. And if your going forced induction, make sure the cam you use is a blower cam, there is a difference, Mike. SCT Tuner. P.S. Good Luck!

[Protree750]

1st thing you should be looking at is what type of pistons do you have, this is your main source of low compression. Flat top pistons need to be notched, dome pistons - forget about boost. As for cylinder heads, the higher the CC obviously a bit better for a boost application, but from personal experience the AFR 185 are great heads and for big boost apps AFR 205 are king.

[ShadowMaster]

Depending on how big of a turbo you plan to use and how much boost you want to run you shouldn't lower the compression too much. Compression that is too low will give you a sluggish engine when driving with low boost numbers. Tuning is also problematic when compression is too low. Typically, don't drop below 9:1 for most applications. If you have a good tune and access to good quality fuel then 9.5:1 is preferred.