Cylinder Heads.. Trickflows any good..?

**NightTrain66** · 05-06-2014, 10:46 PM

My opinion would be a fully ported Trick Flow 23 degree head with 2.08/1.60 valves and Comp 977 dbl springs. $2100 for a set up like this.

You can always upgrade to better quality valves and springs (at a higher price) but the Ferrea 6000 series valves and Comp 977 springs with steel retainers are what comes on the $2100 set of heads.

Same heads that are on Troys turbo GMC Sonoma from last years shootout (although his was a solid roller).

Just remember a N/A set up likes compression (12-12.5 to 1) and a N/A cam (244/252 .637/.621 109 LSA) where as a turbo set up wants low compression (8.5-9.5 to 1 dependingh on boosta nd fuel used) and a turbo cam (low duration, wide LSA) so when boosted you will need to swap pistons and camshaft.

There is not really a compression ratio and cam that works well with both and if you try and compromise you end up with a set up that doesn't work well N/A or turbo.

Lloyd

**MoeHorsePower** · 05-07-2014, 08:47 AM

Originally Posted by NightTrain66

Just remember a N/A set up likes compression (12-12.5 to 1) and a N/A cam (244/252 .637/.621 109 LSA) where as a turbo set up wants low compression (8.5-9.5 to 1 dependingh on boosta nd fuel used) and a turbo cam (low duration, wide LSA) so when boosted you will need to swap pistons and camshaft.

There is not really a compression ratio and cam that works well with both and if you try and compromise you end up with a set up that doesn't work well N/A or turbo.

Lloyd

Listen to this guy^^, I had a customer that built a NA motor then decided to go turbo with the same parts, the car sounded nasty with the narrow LSA (108) and with the proper compression and cam should of made easily 600 rwhp, but with his set up, barely made 400, all of the boost was going out the exhaust..
I can tell you that I tune a lot of customers that have LE setups, and the torque and power band is flat as a board, meaning? they pull hard all the way to the red line..

**birdie2000** · 05-07-2014, 12:10 PM

Originally Posted by NightTrain66

all aftermarket haeds have thicker decks and can handle more boost beforedeck thickness becomes a problem.

Anything under 700 RWHP will be fine using stock GM heads as far as deck thickness goes. If it lifts the heads at that HP level or below it can usually be traced back to something lean, too much timing, too hot of a plug, too much compression, too low octane, etc, etyc or any other reason that is basically another word for detonation. If the stock GM head lifted, an aftermarket would have done the same thing at this HP level under those conditions.

There are people making even more power on stock castings but I am not here to argue about the HP limit or if aftermarket haeds are better choices after XX boost or after XXX RWHP level. I am just saying the average 550-650 RWHP set up doesn't need to worry about it. I do believe if you have plans for over 600 RWHP that an aftermarket head would be better to start with for a few reasons.

The 54 cc's that come on the 21 degrees can DEFINITELY be made smaller (as small as 48 cc).

Lloyd

Thanks for the info Lloyd!

Why do you believe it's better to start with aftermarket heads if you have plans for over 600rwhp?

My goals will be in the 550-600rwhp range with a 6 speed. I have a very stout 383 bottom end with -31cc pistons that will be assembled shortly. I don't have deck height measurements to figure out exact compression ratio yet, hope to get the proper measurements when I have it assembled. I'm thinking though that I'll need heads in the 52-48cc range though to get a compression ratio of around 9.5:1. The car will be purely a street car, want a baby cam that sounds and drives like stock, won't rev very high (probably 6000rpm max). The most important part of this whole setup is that it has excellent drivability, is very reliable, and runs on 93 octane. I'd entertain the thought of using meth but don't want to unless necessary. I thought starting with the 21* heads would be a good start because they would have the right chamber size for compression, has thicker deck surface which can only help reliability, and the ports will flow better than stock but are still 185cc so it'll have very crisp throttle response out of boost. I could always port later down the road if I feel the need.

Am I off base in my thinking? Getting ported stock heads would probably be a little bit cheaper, but reliability is my number one concern over anything else. Want to be able to beat the crap out of this engine on a semi-daily basis for years to come.

**NightTrain66** · 05-07-2014, 04:39 PM

only reason for stock heads on a 600+ RWHP boosted set up would be budget reasons but then again, if you are actually gonna male 600-800 RWHP by the time you add everything up for turbo, intercooler, fuel system, tuning (or DFI set up), etc, etc . . . . . . the extra $500 or so to get aftermarket heads should be no problem.

Aftermarket heads have bronze guides, a lil thicker deck as mentioned, offer more potential for porting and larger valve sizes, etc. They will just make more power assuning the same compression ratio.

The 21* TFS heads would be the head to start with but dont worry about losing low end power or drivability and losing "velocity" by porting them and using larger valves.

The right cam and the tuning will control the low end power and how well it accelerates at low RPM with no boost.

If you are running 6-8 psi of boost a 211/211 .541/.541 112 LSA cam will have plenty of low end power and drivability from idle until boost comes it. It will build boost quickly and make tons of mid range TQ and have no problem pulling past 6000 RPM. If running more boost a cpl degrees more duration and slight increase in LSA would be needed at 9.5 to 1 on 93 octane fuel.

Lloyd