RU-QWIK

iTrader: (3)

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 are your thoughts?

Jason

Batass

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.

RU-QWIK

iTrader: (3)

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?

Jason

Batass

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.

RU-QWIK

iTrader: (3)

Stamped on the head where the acc. bracket bolts to,

223 6794 167T F5156 04 03

Thank you for the help !

Jason

Batass

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.

RU-QWIK

iTrader: (3)

Thank you very much for your time and sharing knowledge !!!! I'll get another thread and PM you the link...

Jason