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For a single pattern cam with a 255 dur. @ .050, the thing will obviously be shaky at low rpm's.
Since it has so much duration, will fuel be wasted at low rpm's (will it escape out the exhaust port before it closes), or will vacuum just suffer as well as low rpm torque (will some of the fresh charge just be pushed back into the intake man.)
Yes fuel will be wasted and yes vac. will be poor at best and reverse pump fuel air charge into the intake. NO gas mileage, soggy bottom end and no power brakes. Makes for a miserable, hard starting, non idleing, plug fouling, ill tempered, TURD! on the street.
rats!
I wish that idiot I bought the engine from hadn't put that thing in.
Welp, I think I may have to bite the bullet and put in a new cam, which I'm sure will require many new posts when I get into it and don't know what to do next.
Until then, Can anyone recommend a good profile for street use. I'm guessing between 215 and 225 degrees duration.
I have a big block 402 with stock iron heads ( I think 2.09, 1.88 valves but not sure), and roller rockers. Bore is about 4.128, stroke 3.76. I'm putting it in a chevy pickup with a standard 5 speed, 3.89 rear.
The pistons have a little pop up, I don't know how many cc's. I don't know the casting numbers off hand, but when I had the heads off I took the number and used a BB book I have to find out the cc size. I calculated static compression very liberally (assumed a zero deck height, thinnest gasket available) and came up with less than 10:1.
The engine probably wasn't built properly for a cam that radical, I'm not even sure if it has rectangular ports.
It's basically pretty stock, so I think replacing that cam with a good street one will work out pretty well.
I'm just not sure how to combine the overlap with duration for best results.
Also, I know I can't use old lifters on a new cam, but can I use old pushrods?
I'd like to use hydraulic lifters for the ease of adjustment.