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mikep · 06-02-2002, 04:04 PM

.125" domed pistons with .490" lift isnt even going to get close to valve to piston interference problems.

A 383 with vortech heads and that cam with 10+:1 compression will give too much lower end torque with those 3.73 gears IMHO which looks good on paper but is a hindrance to a good launch in the real world. With a 383 you'd really need 242-245 degrees duration and thats with some pretty healthy port sizing (200+ cc) to build good midrange to top end power. Otherwise you'll run out of steam under 6K . Sure you could build a 383 with the 286 cam and be building 400+ ft lbs under 3200 rpm but what good will it do you if your tires are spinning the whole time?

All I can say is I used to race a lot of guys with 383's and short duration cams (under 250 at .050") who all had the same problem. Too much low end torque. They'd smoke it off the line and I'd beat them by a few seconds and theyd be pissed because they got beat by a Ford. OK it was a 480 horepower 351 cleveland but it was still a ford. Big ports, hi rpm, hi compression, and long duration is what its all about in small blocks. They had 12 second cars running 14 seconds because if you can't hook it up you are screwed . Add to that the lack of weight in the back of a truck and it makes even more sense to stay away from long strokes and bottom end torque and go more towards stronger mid range and higher rpms and thats where the faster revving 350 with its shorter stroke shines. Not to mention the fact that its easier ( read cheaper) to build and especially balance a 350 with good quality hi rpm capable parts. A lot of guys swear by cast cranks. Ive broken enough to not be convinced of their hi rpm longevity. Steel's the way to go.

One note on porting the chevy heads. It'd cost quite a bit more than buying decent off the shelf items to have a quality porting job done by someone who knew what they were doing. Theres just so many really good heads out there these days that it doesnt make sense to use clapped out chevrolet castings any more. A $1200 port job on a set of heads plus plates, springs and studs is putting you into the $1400+ range and thats on your heads. $700 will buy you aftermarket heads that flow as well and are ready to bolt on. I bought my sportsman II heads new in the box with valves, springs, and seals for $600 for the set out of the paper and I know Iv'e paid $1200 to port a set of angle plug bow ties that flowed about the same.

06-02-2002, 04:04 PM	#7
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	.125" domed pistons with .490" lift isnt even going to get close to valve to piston interference problems. A 383 with vortech heads and that cam with 10+:1 compression will give too much lower end torque with those 3.73 gears IMHO which looks good on paper but is a hindrance to a good launch in the real world. With a 383 you'd really need 242-245 degrees duration and thats with some pretty healthy port sizing (200+ cc) to build good midrange to top end power. Otherwise you'll run out of steam under 6K . Sure you could build a 383 with the 286 cam and be building 400+ ft lbs under 3200 rpm but what good will it do you if your tires are spinning the whole time? All I can say is I used to race a lot of guys with 383's and short duration cams (under 250 at .050") who all had the same problem. Too much low end torque. They'd smoke it off the line and I'd beat them by a few seconds and theyd be pissed because they got beat by a Ford. OK it was a 480 horepower 351 cleveland but it was still a ford. Big ports, hi rpm, hi compression, and long duration is what its all about in small blocks. They had 12 second cars running 14 seconds because if you can't hook it up you are screwed . Add to that the lack of weight in the back of a truck and it makes even more sense to stay away from long strokes and bottom end torque and go more towards stronger mid range and higher rpms and thats where the faster revving 350 with its shorter stroke shines. Not to mention the fact that its easier ( read cheaper) to build and especially balance a 350 with good quality hi rpm capable parts. A lot of guys swear by cast cranks. Ive broken enough to not be convinced of their hi rpm longevity. Steel's the way to go. One note on porting the chevy heads. It'd cost quite a bit more than buying decent off the shelf items to have a quality porting job done by someone who knew what they were doing. Theres just so many really good heads out there these days that it doesnt make sense to use clapped out chevrolet castings any more. A $1200 port job on a set of heads plus plates, springs and studs is putting you into the $1400+ range and thats on your heads. $700 will buy you aftermarket heads that flow as well and are ready to bolt on. I bought my sportsman II heads new in the box with valves, springs, and seals for $600 for the set out of the paper and I know Iv'e paid $1200 to port a set of angle plug bow ties that flowed about the same. __________________ No truck :-( Last edited by mikep; 06-02-2002 at 09:01 PM.