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531 Head questions...

deadken

Member
Joined
Mar 31, 2009
Location
Long Island, NY
I have (2) 531 heads lined up for me to buy this weekend. They are from salt water Penta engines (no 2.5l bottom ends at the moment). One is still on the 2.3L block.


1) What makes it not worth buying a 531head? (besides price)

2) I always see a bunch of corrosion on the #4 exhaust port, how much is too much? (how to tell if it is now scrap?)

3) Any easy way to see which cam is in it? (I'll be looking at them with the guy, so minimal disassembly method preferred)

4) What is the going rate for a stock 531? (USD)


BTW: I was thinking of buying both and letting a machine shop test / inspect them to see if they are good. If one is bad (or the worse of the two) it'll be used for slicing up to see how much material the machine shop can safely port off.
5) Does that sound like a reasonable plan?

6) Is it worth $400 to find out? Or, should I only buy the better of the two and put the $200 or so towards shipping the head to a shop that already knows how much material can be safely removed?


-Thanks!
 
they have larger intanke ports and a better positioned spark plug. If you have headwork done on a 530 head it can be modified to be just as good. The 531 is just a better starting place but both versions can get you to a 8v power goal.

If you can look at the carb setup on the penta engine the head came from that will give you an idea of the cam in there. A single carb engine will have an A cam. A dual carb engine will have a V cam.

I had the corroded port welded up on my 531 and head flowed by D&F performance in berlin NJ. The heads I've gotten done by them are excellent.
 
they have larger intanke ports and a better positioned spark plug. If you have headwork done on a 530 head it can be modified to be just as good. The 531 is just a better starting place but both versions can get you to a 8v power goal.

If you can look at the carb setup on the penta engine the head came from that will give you an idea of the cam in there. A single carb engine will have an A cam. A dual carb engine will have a V cam.

I had the corroded port welded up on my 531 and head flowed by D&F performance in berlin NJ. The heads I've gotten done by them are excellent.

do you have results from the flow bench you can post?
 
If you are planning on running a custom camshaft with over 12mm of lift and making 175+ HP NA or 350+ Turbo, a 531 head may be worth the effort. Otherwise, it's not necessary and may reduce your drivability, torque and efficiency at lower rpm.
 
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