Any reply's are welcome. To start off, I'm buying a 350 L98 block and am going to change it into a 383 stroker. I have to buy the parts for the engine and my friends dad is putting it together and in the car. It is going to be a super ram, 58 mm, and SPR RM manifold. I am looking into almost entirely into driveabilty, gas mileage (this shouldnt be a problem with the TPI, just at least 15 on highway), and TORQUE. It will just be street raced. Anyway, the first question;
1) About how good would you rank these heads for a 383 TPI : Pro Iron 64cc 220 Runner SBC Chevy HEADS A high quality high performance 23 degree cylinder head that features phosphor bronze exhaust valve guides for compatability with all valves.Uses standard rockers,guide plates and other parts.Set up for 2.02 intake valves and 1.6 exhaust valves.Flow numbers are off the scale.This auction is for each head,but unlimited quanities are on hand.Why pay more when you can buy the best for less.Reserve is $200.Buyer pays freight.

2) explain what the difference between 1.6 and 1.5 roller rockers (I know the 1.6 lift higher, but what does the lifting do for Torque) Are steel ones better for driveability/torque and which size 1.5 or 1.6.

3) what would the optimal kind of valve springs for the 383 TPI for torque be. The compression will be around 9.5:1.

4) what do 6.0" rods compared to 5.7" rods due for driveability, torque, etc.

I am making an engine build up sheet, and as far as the exact parts are concerned, I need to know exactly what these parts will do for me. Thanks once again, any help is appreciated.

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IROC-Z :
Jet Black, Tinted Windows, Racing 5 Spokes, Big Block Hood, 91-92 Ground FX, 91-92 Z28 Spoiler, Headlight and Tailight Covers, Lowered. BAD @$$!!

 

2) Since a cam can't possibly supply enough lift in a V8 engine they use a rocker ratio to provide extra lift. Lets say a cam rated at .500 lift uses standard 1.5 rockers. The actual cam lobe only lifts .333. Multiply that by the 1.5 rocker and you get .500 lift at the valve. Swap out the 1.5 rockers for some 1.6 rockers and the .333 lobe lift now becomes .533 lift at the valve. To increase the rocker ratio, the rockers move the pushrod closer to the rocker pedestal. There may be some interferance in the pushrod hole in the head when doing this. Some heads already have the hole enlarged. Others need a bit of grinding.

3) Use the valve springs recommended by the cam manufacturer.

4) 5.7" rods in a 383 already require some block clearancing to get them to work. Adding 6" rods will require more. To use a longer rod and still keep the piston from going out the top of the cylinder, the wrist pin must be moved higher up the piston. A 5.56 rod has the wrist pin in the perfect position. A 5.7 rod piston moves the wrist pin into the oil control rings. A 6" rod piston will move the wrist pin even higher risking the chance of having poor ring area strength. There's also a chance of having the con rods hit the cam lobes depending on what cam you choose to use.

I had a simple short rod 383, carbed, 30 year old cast iron double hump heads that pushed my car into the high 11's. I never built the bottom end but after racing it for 2 years the stock cast pistons and factory rod bolts finally let go. Just goes to show that all the fancy parts aren't required but some of them will make the engine last longer.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.69
Best MPH on a time slip: 121.52 altitude corrected to 127.76
Altitude corrected rear wheel HP based on power to weight ratio: 504.5
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley


[This message has been edited by Stephen 87 IROC (edited May 30, 2001).]