PRC 237cc people come in
12-11-2012, 11:04 AM
#1
PRC 237cc people come in Let me know what you got, numbers, times etc, anything will do!
I seen the hot rod shootout for heads, but other than that and a couple other threads theres next to no results for these heads despite them being out a while.
Im looking at running these on my 408, but before pulling the trigger
I want to make sure they will be a good choice. The other 2 im looking at are the TFS 235's and AFR 230's but theeres plenty of info on those.
So, PRC 237cc people post up!
I seen the hot rod shootout for heads, but other than that and a couple other threads theres next to no results for these heads despite them being out a while.
Im looking at running these on my 408, but before pulling the trigger
I want to make sure they will be a good choice. The other 2 im looking at are the TFS 235's and AFR 230's but theeres plenty of info on those.
So, PRC 237cc people post up!
12-12-2012, 12:07 AM
#5
4.083 bore 418ci
Made 546rwhp through a unlocked glide with a 4,600 rpm verter. Motor is laying down though at 6,700ish rpm due to valve float which it shouldn't. I am swapping out the stock 115g valves for a turned down LS3 valve. $300 to shave 28g's from the intakes is well worth it. If it cleans up the issue, I bet there is 20-25rwhp on the table. I am also leaving power on the table with a 1 3/4 stepped to 1 7/8 header. I really need to get a 2" primary on it.
I am changing a few other things IE EWP, Porting the Super Vic intake, Bunmping the compression a little. Hoping the valves fix the float and with the other changes I can get it to go 10.20's with the current N20 verter.
Times in sig for my Farmtruck
Made 546rwhp through a unlocked glide with a 4,600 rpm verter. Motor is laying down though at 6,700ish rpm due to valve float which it shouldn't. I am swapping out the stock 115g valves for a turned down LS3 valve. $300 to shave 28g's from the intakes is well worth it. If it cleans up the issue, I bet there is 20-25rwhp on the table. I am also leaving power on the table with a 1 3/4 stepped to 1 7/8 header. I really need to get a 2" primary on it.
I am changing a few other things IE EWP, Porting the Super Vic intake, Bunmping the compression a little. Hoping the valves fix the float and with the other changes I can get it to go 10.20's with the current N20 verter.
Times in sig for my Farmtruck
12-13-2012, 10:09 AM
#6
4.083 bore 418ci
Made 546rwhp through a unlocked glide with a 4,600 rpm verter. Motor is laying down though at 6,700ish rpm due to valve float which it shouldn't. I am swapping out the stock 115g valves for a turned down LS3 valve. $300 to shave 28g's from the intakes is well worth it. If it cleans up the issue, I bet there is 20-25rwhp on the table. I am also leaving power on the table with a 1 3/4 stepped to 1 7/8 header. I really need to get a 2" primary on it.
I am changing a few other things IE EWP, Porting the Super Vic intake, Bunmping the compression a little. Hoping the valves fix the float and with the other changes I can get it to go 10.20's with the current N20 verter.
Times in sig for my Farmtruck
Made 546rwhp through a unlocked glide with a 4,600 rpm verter. Motor is laying down though at 6,700ish rpm due to valve float which it shouldn't. I am swapping out the stock 115g valves for a turned down LS3 valve. $300 to shave 28g's from the intakes is well worth it. If it cleans up the issue, I bet there is 20-25rwhp on the table. I am also leaving power on the table with a 1 3/4 stepped to 1 7/8 header. I really need to get a 2" primary on it.
I am changing a few other things IE EWP, Porting the Super Vic intake, Bunmping the compression a little. Hoping the valves fix the float and with the other changes I can get it to go 10.20's with the current N20 verter.
Times in sig for my Farmtruck
12-13-2012, 10:26 AM
#7
I got the heads used. The seller replaced the springs with the .650 spring which I don't think are strong enough to control the 115g valve.
I have a set of new .675 spring here that I could swap in, but I am still running a 5/16 .080" push rod. From what I understand, there will be a bit of deflection. Others have also brought up issues running factory rockers with that much spring pressure. Being I don't daily drive it, I am not too concerned about valve tip erosion.
I am however putting powdered metal guides in too since I might put a heavier spring in.
In the event the new valves don't fully cure the unstable valve train issue I am seeing, I will swap to the .675 springs I have and upgrade the push rod to a 5/16 .120" wall since TSP has advised the heads are not machined for anything bigger than a 5/16 push rod.
I have a set of new .675 spring here that I could swap in, but I am still running a 5/16 .080" push rod. From what I understand, there will be a bit of deflection. Others have also brought up issues running factory rockers with that much spring pressure. Being I don't daily drive it, I am not too concerned about valve tip erosion.
I am however putting powdered metal guides in too since I might put a heavier spring in.
In the event the new valves don't fully cure the unstable valve train issue I am seeing, I will swap to the .675 springs I have and upgrade the push rod to a 5/16 .120" wall since TSP has advised the heads are not machined for anything bigger than a 5/16 push rod.
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12-13-2012, 02:06 PM
#9
There's a lot of creative things TEA is doing with the TFS castings that make them #1 in my book. Turned down LS3 valves, PM guides, springs that can work with either YT Ultralites or Stockers, larger pushrod provisions out of the box. Mamo is doing a lot of similar things with AFR heads but at a higher cost.
Will a big *** heavy valve with huge springs and 5/16" pushrod work? Sure. Will it work as well as super light valves, larger pushrods, optimized springs for the rocker and be as reliable? Nope.
Will a big *** heavy valve with huge springs and 5/16" pushrod work? Sure. Will it work as well as super light valves, larger pushrods, optimized springs for the rocker and be as reliable? Nope.
12-13-2012, 04:25 PM
#11
I looked at the AFR 245's, TFS heads and the PRC 237's.
According to AFR when I spoke to them, the intake valve that comes with them is even heavier than the PRC's. Not sure about out of box TFS heads.
I believe PRC offers the 237's with PM guides and TSP might work something out with the valves, again, I bought mine used so I don't know.
I am actually sending them to TEA to have the LS3 valves put in them, pm guides, gonna see about clearencing for bigger push rods. All said and done, my used heads probably will cost a little less than the TEA modified TFS heads
I agree that a lighter setup will yeild better results, less headaches and more reliability.
According to AFR when I spoke to them, the intake valve that comes with them is even heavier than the PRC's. Not sure about out of box TFS heads.
I believe PRC offers the 237's with PM guides and TSP might work something out with the valves, again, I bought mine used so I don't know.
I am actually sending them to TEA to have the LS3 valves put in them, pm guides, gonna see about clearencing for bigger push rods. All said and done, my used heads probably will cost a little less than the TEA modified TFS heads
I agree that a lighter setup will yeild better results, less headaches and more reliability.
12-13-2012, 05:00 PM
#13
How aggressive is your cam?
You can clearly see spring surge on my dyno sheet below 6,600. 4,600-5,700 shows initial surge, clears up a bit then comes back in a horible fasion at 6,500-6,600.
As David Vizard explains in his book about valvetrain dynamics, you can see a stability problems start, go away and come back at different rpm's due to the harmonic frequencies. To make a blanket statement that below 6,600 you should be ok, not sure if I can totaly agree with that. You could be killing the springs faster than normal due to the early surge that isn't quite bad enough to cause lower rpm instability. But hey, what do I know.
You can clearly see spring surge on my dyno sheet below 6,600. 4,600-5,700 shows initial surge, clears up a bit then comes back in a horible fasion at 6,500-6,600.
As David Vizard explains in his book about valvetrain dynamics, you can see a stability problems start, go away and come back at different rpm's due to the harmonic frequencies. To make a blanket statement that below 6,600 you should be ok, not sure if I can totaly agree with that. You could be killing the springs faster than normal due to the early surge that isn't quite bad enough to cause lower rpm instability. But hey, what do I know.
12-13-2012, 05:01 PM
#14
I dont actually have the cam yet. I wanted to settle on a set of heads, then Pat G is going to spec it out for me.
I dont plan on having a super aggressive cam, this is a daily driven street car and I want it on some nice easy on the valvetrain lobes (or as easy as I can get away with). also using stock rockers so lift is going to stay at or under .630
I dont plan on having a super aggressive cam, this is a daily driven street car and I want it on some nice easy on the valvetrain lobes (or as easy as I can get away with). also using stock rockers so lift is going to stay at or under .630
12-14-2012, 04:13 PM
#16
The tfs and afr valves are all around the same weight if not more in some cases. Its a really hard decision to pick a set of heads in this price range. The 247s are to large, the afr and tfs by the time I get the things I need end up at $2500 and then theres those ohh so tempting small bore ls3 heads. Im still floating that idea around since I dont have an intake yet.
12-14-2012, 06:56 PM
#17
It took me 4 months of research before I decided on heads for my 408. Take some time to weigh everything out and see which will be best for your combo and any future combo.
Neiter TEA TFS, AFR or PRC heads will disappoint you. Personally I would stay w/a cathedral style head. IMO.
Neiter TEA TFS, AFR or PRC heads will disappoint you. Personally I would stay w/a cathedral style head. IMO.
12-14-2012, 08:15 PM
#18
What did you decide to go with combo/numbers?
In comparison to the small bore ls3 heads the cathedrals match their flow plus some untill .600 lift where the ls3s start to take a jump but so littke of my time is that high i dunno. The ls3 is mever more than 2-4cfm off from the 237s, but the valve is larger and with my 4.030 im afraid will shroud it some compared to the 4.06 bore they flow them on.
I could always move up to the 247s i suppose but ughh im just not sure
In comparison to the small bore ls3 heads the cathedrals match their flow plus some untill .600 lift where the ls3s start to take a jump but so littke of my time is that high i dunno. The ls3 is mever more than 2-4cfm off from the 237s, but the valve is larger and with my 4.030 im afraid will shroud it some compared to the 4.06 bore they flow them on.
I could always move up to the 247s i suppose but ughh im just not sure
12-14-2012, 09:46 PM
#19
call rich at WCCH and ask about these please do all the research you can i did for a long time before i got my heads
http://proheads.com/WCCH245.html
http://proheads.com/WCCH245.html