Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
I have a set of Pro Topline cast iron heads, they have 1.94/1.50 valves, screw in studs, straight plugs,etc. Don't know much more about them... They have S-RT cast into them below the "ProTopline".
What sort of gains should be expected by putting these in place of a set of 350 TBI heads? The engine is a 355 TPI, stock throttle body with air foil, ported plenum, stock runners, ported Accel base, TPIS adj. regulator, Holley 24lb. injectors, 1 3/4" long tube headers, dual 2.5" exhaust, Summit 1103 cam - 214/224 duration .442/.465 lift.
I have an LT-4 Hotcam and 1.6 Roller rockers that I may put in too, but am thinking it is too much for the heads. I am hoping for good gas mileage too, something over 20 mpg as I am getting 20-21 now in the car (700r4 & 3:55 rear).
These heads any good?
This engine is in my 57' Chevy which is about 2900 lbs.
What chambers are they? 76 or 64? I used to have a set of those heads, and they aren't bad. They would be better than the TBI heads. Should be at least a 20hp improvement. They dont have the heart-shaped chambers, but they have good runners.
I think that cam might be a bit big. They have big tall valve guides. You'll have to figure out what the max lift for em is. They are the same as RHS's stock replacement heads, so you could call them to find out.
What chambers are they? 76 or 64? I used to have a set of those heads, and they aren't bad. They would be better than the TBI heads. Should be at least a 20hp improvement. They dont have the heart-shaped chambers, but they have good runners.
I think that cam might be a bit big. They have big tall valve guides. You'll have to figure out what the max lift for em is. They are the same as RHS's stock replacement heads, so you could call them to find out.
I don't have a clue as to the chamber size.... What can I measure/ look for to find that out? I need to know so I can figure compression ratio. I am looking at the Comp cams Xtreme fuel injection XFI, 202/212 - 550/546 with ls of 113, I think that may work well with the Tuned port and heads... Sound better than the hotcam?
There should be some stamped numbers on the outside accessory side of the head. Should be around 8 digits. I can tell you what they mean. That cam is more lift than the hotcam. I dont know how much lift the heads can take until the spring retainer will contact the valve guide. I know the valve guides are large. I don't know where you can find the information except calling up RHS.
Ok, 67cc chambers, the 94 means 1.94 valves, 167 is the runner size. For the cam, I'm no cam guru, but these heads dont flow big. They will match the tpi well, which doesnt flow big either. Great for low end power. I don't think you will want a big lift cam. I think you will want a lower lift around .500 or so and lots of duration. Keep the valve open longer, instead of higher, letting the high velocity do its work.
I'd start a new thread for the cam. Id also be interested in what the cam guys say.
Ok, 67cc chambers, the 94 means 1.94 valves, 167 is the runner size. For the cam, I'm no cam guru, but these heads dont flow big. They will match the tpi well, which doesnt flow big either. Great for low end power. I don't think you will want a big lift cam. I think you will want a lower lift around .500 or so and lots of duration. Keep the valve open longer, instead of higher, letting the high velocity do its work.
I'd start a new thread for the cam. Id also be interested in what the cam guys say.
Thank you very much for your time and sharing knowledge !!!! I'll get another thread and PM you the link...
