Hi guys, who has purchased Trick Flow or other brand aftermarket small block Chevy heads in 58cc chambers? I am ONLY interested in 58cc heads. I have a 327 and need this chamber size to achieve 9.7:1 static CR with my speed pro flat top pistons. I can't use a 64cc or larger head. Anyhow, the Trick Flow cnc profiled Aluminum heads are very reasonably priced, around $1300 fully assembled with 1.94/1.5 valves and all. I'm sure the 1.94 valves are big enough, my 327 is very short stroke compared to a 350 or larger small block, and will thus tax the head's flow capacity less. I have a Holley Stealth Ram on this engine and burn my own chips, and this engine is very fresh and has nearly perfect ring seal, so I would really like to see this thing perform. I have some home ported and polished 305 58cc iron heads with 1.84/1.5 valves in them (081 casting #), and the car runs really well but I need to go faster, always! I shift around 6200, so I'm sure these heads are taxed out at that point.

Please let me know what you run! Also, I didn't see any flow #s on the 58cc aluminum Trick Flows, anyone know?

 

23 Degree 175 Airflow Chart, 3.766" Bore

Lift Value: Intake Flow
(CFM): Exhaust Flow
(CFM):

--------------------------------------------------------------------------------


0.100 61 53
0.200 127 105
0.300 180 142
0.400 216 160
0.500 242 172
0.600 242 180

NOTE: Tests conducted at 28" of water (pressure); exhaust with 2' pipe.


23 Degree 175 Airflow Chart, 4.000" Bore

Lift Value: Intake Flow
(CFM): Exhaust Flow
(CFM):

--------------------------------------------------------------------------------


0.100 62 57
0.200 127 109
0.300 180 142
0.400 219 167
0.500 242 181
0.600 245 192

NOTE: Tests conducted at 28" of water (pressure); exhaust with 2' pipe.

Source is TrickFlow

23 Degree 175 Aluminum Cylinder Heads for Small Block Chevrolet

 

Thanks, I have the 4" bore with the 327. Has anyone run these heads? They should be good to run 13 flat, no?

 

I know you do, I just included the 3.766 flow numbers for reference. These heads have better intake flow and much better exhaust flow than the L31 vortecs. I have seen many mildly cammed 350 Vortec engines make over 400 HP. 350-370 HP is not out of the question with these heads and a properly matched cam.

 

Fast, the cam spec'd out in my signature is newly installed. However I really want to go roller because the narrow band O2 does not like the lazy, dirty hydraulic cam idle and it annoys me having it smell rich all the time. What would you recommend for a cam in the 327, something like the LT4 hot cam?

 

Don't forget that you can get 64cc heads and have them milled. However it sounds like the Trickflows mentioned above will work quite well for you application.

 

I hate milling heads, especially brand spankin new heads, because then you have to worry about milling the intake side and hoping everything works out and fits right. The 58s have more limited selection than the larger CC heads, but there are a few good choices it looks like. There was another company in Summit that had iron 58CC heads with 2.02/1.6 valves. Those were CHEAP, around $600 assembled, but they didn't have the CNC profiled chambers that the Trick Flows did. I also realize that valve size does not tell the whole picture of how well heads will flow.

 

I'm with you on that one- I hate milling perfectly good new heads, too.

FYI- that 275DEH cam isn't a bad piece, but it's not really for an EFI engine. "Overlap" is the fly in the ointment with EFI engines. The more there is, the tougher it is to tune for idle and low RPMs- drives O2 sensors nuts. EFI cams are typically designed with much wider LSA to reduce overlap. Even roller cams are in the same boat. Flat tappets actually get from zero to .050 lift FASTER than an equivalent roller cam in most cases. It's only above that point that roller cams leave them in the dust.

Your 275 DEH runs on a rather narrow 110* LSA. RARELY will you find a street EFI cam that's any narrower than 112* LSA (the Hot cam is 112* LSA). Your same cam on a 114* LSA would idle and tune much easier against an O2 sensor.

 

Damon, I almost bought the Summit .465/.488 114 LSA cam, that I have used in a BB Chrysler with success before. Dammit! That would have been perfect probably, and really really inexpensive. I replaced an Isky 280HL with the 275DEH, thinking the O2 would be happier with it. The Isky was .485"/.485" 232@0.05, 108 LSA, and surprise!! The 275 DEH is milder on the intake side, but on the exhaust side, where it counts, it is nearly an identical lobe to the Isky. It sounds absolutely identical and runs the same. Oh well, what a waste of time.

 

If you're running headers (I assume you are given the rest of the mods) many people have found it helpful to use a heated O2 sensor. The stock unheated unit cools off too fast and you end up dropping in and out of closed loop. Not like this is going to magically fix your core problem, but it might make your O2 readings more "sane" and predictable so you can find a way to tune arouond the rest of the combo as best you can.

 

Um, I am running a 3 wire heated O2. I am a little ahead of that. There is no real way to make a narrow band (or even wide band) sensor accurate given the amount of overlap this cam has. I can definitely tune around the sensor's limitations. Even now the idle quality is excellent, just the exhaust smells strong. I'm about to put cats and a friekin air pump on this car so it doesn't smell so bad on my clothes after being around it running.

 

since you have a 4 bore I would run some AFR eliminator 180's milled. That and a decent cam and that motor will scream.

 

Just an FYI, the Trick Flow 175s are 56cc, not 58cc. So you'd have a little higher CR. Also, the 175s are not offered CNC. It's the 195s that are offered CNC, and those are 64cc, up from 62cc(non-CNC).

Performance-wise, either head should easily support over 400hp. And with the different CRs, you'll prolly get about the same results using either head with that cam.

 

Thanks. I am not keeping the cam I have, I will likely go with something like the LT4 hot cam with 1.6 rockers. I am sick of the dirty idle with the flat tappet cam.