Reply With QuoteIF YA GO WITH THE NEW HEADS, HOW MUCH FOR THE OLD ONES, ARE YA GOING TO SELL THEM?...BILL.
Has anyone run a set of AFR 357 heads on a blown application? I am thinking of changing from cast merlins to them and would like some info on them as far as power and torque gains or if it is worth it?
IF YA GO WITH THE NEW HEADS, HOW MUCH FOR THE OLD ONES, ARE YA GOING TO SELL THEM?...BILL.
call Larry's engine in AZ, Talk to LArry and he'll answer all your questions
for blower motor applications.
Originally posted by hulshot
Has anyone run a set of AFR 357 heads on a blown application? I am thinking of changing from cast merlins to them and would like some info on them as far as power and torque gains or if it is worth it?
Go ahead and send me those old merlins when you are done with them....
i saw a dyno test done on a 8-71 blown 496cid BBC where the owner swapped AFR's 315, 335 and 357 heads onto the motor without changing anything else. The power was exactly the same. Keep in mind he didn't change the camshaft, but still, there was no change up or down. According to Tony at AFR, unless you have a very large displacement engine, you dont need anything larger than the 315's.
What you are not entering into the equasion is RPMs. If you want to spin that motor, there is going to be one hell of a big difference with the bigger heads....
I do want to sell my heads if anyone is interested. they are complete and ready. send some money and I will ship them. They are merline 345 with some intake work and big valves with k 900 springs and titanium keepers with 10 degree locks.
How many $$$?
from what I have learned is that you really dont need the huge volume to make the power.(unless your gonna be spinning 7500+ rpms)
Go with the 335's and have the exhaust ported.
Racer
The reason for the lack of power diference on the AFR heads is that the smaller intake port feeds the engine with all it needs with the blower. The exhaust ports are the same size so there is no difference there either. The difference would be comparing the AFRs to your old heads or anything else. That is because the AFRs have the best flowing exhaust port around! just compare the numbers! On a blower motor if you run 14.7 lbs boost (1 atmosphere),you effectively double the amount of air ingested, so you make double the exhaust gas too! On a 468 thats 936 inches of exhaust through a port designed for a 454! You want the best flowing exaust port you can get.(the AFRs). and since they are cnc ported, you just install them and go. I went from Canfield (ported) 355s to AFR 335s (out of the box )and picked up 2-3 mph on my 572. TIMINATOR
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