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Cylinder head decision

1K views 6 replies 4 participants last post by  glen242 
#1 ·
AFR claims 430 HP @5500Rpm and 470 ft lbs @ 4500 Rpm on the link below. Any thoughts on what would happen to those numbers if you replace the 180's with the 195's with out changing anything esle??

Also I think those are old numbers on there old heads.(I could be wrong)If Im not wrong what do you think the numbers would be like with there new street eliminator 180's and there new street eliminator 195's with all the same parts??

Thanks in advance

http://www.airflowresearch.com/chevy_dyno.php
 
#2 ·
You have been recommended at least three different head sizes depending on what you want to do with this car. Its NOT about top HP numbers, its about drivability and a nice broad power band. You said its going in a street rod, so throw in throttle response also. Leads to a 180 head. Since all the top head manufacturers products come within 10-15 HP of each other, you really should find the best deal on a 180 cc head instead of just locking in on the most expensive. Could save $300 and go Dart Pro 1 180 heads and you'd never tell the HP difference between them and the AFR.
 
#3 ·
^^^^agreed

keeping everything the same you really wouldn't see much of any hp differecne between the 180 heads and the 195 heads because to take advantage of the extra runner volume you would need to increase your lift.

this is my personal opinion but i think that those numbers on the AFR site are a bit inflated, i dont see a 355 with a 270H cam, 9:1 compression and AFR 180 heads making 430hp, more like 380-390hp. ***never trust what your hear when it's a company trying to sell you somthing, who is telling you it***
 
#4 ·
Thanks for the replys. It sounds like 180's are the way to go. The only thing is I might have a deal lined up on a used set of 195's. The other thing is if I build a bigger motor down the road the 180's would probably choke out a 400ci. If I do get the chance to buy the 195's How much tourqe do you think ill lose?? streetablility?? would they be an issue on a 355?? Maybe ill take a look at the darts if you think I wont notice the difference. What do you think about the performer RPM's??
 
#5 ·
They are ALL good heads. I don't understand cats like you. Now you're talking about what if you build a bigger motor. So? You going to compromise the performance and driveability of your current engine for something you MIGHT do in the future. How about you build your current engine first and worry about your future engine in the future. Its a much more fun hobby doing it that way
 
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