|10-14-2012 10:05 AM|
Don't expect big power from these heads. Poor port flow. Poor chamber shape.
Every other had chevy made is better. If you want power rob the valves and put in another head that has some potential.
Or sell them to someone else that does not know better, to fund getting a aftermarket head.
A world of difference.
It is not worth paying someone to port these heads. If it cost you money to get these heads ready
find a better head.
They will improve with generous porting but pretty much starting with any of the other head castings will
give much better end results.
The Xe274H likes compression
Find a head with a 58-64cc hi perf combustion chamber.
I get good results porting the 4416 head. The small combustion chamber is much better.
and the ports a nicer to start with and end up better too. (1.94x1.60 full port)
The 083 heads from a L98 TPI motor are not bad at all once ported with 2.02 valves.
Vortecs, camel backs, etc.
Some of the other smogger heads are not too bad with generous porting and big valves
441 487 920 etc. 882 and 462624 are the worst of the worst. really bad ex port.
Look and compare the ports to other high perf SBC heads and you will see.
This is a low perf head. The good news is someone will likely buy them just cause they have big valves.
Good for someone that is restoring a 76-80 era corvette L-82 motor.
The lame factory horsepower power rating of these L-82 motors is a good clue why these heads suck if you want power.
|10-14-2012 09:15 AM|
|nobody special||they be 462624, 202/160 82 marine heads. wanna put on 80 4blt 350 3/4 tk w xtrem energy 274 cam headers 2 1/4 exaust to flowmasters w 3 in out. also have steel crank and rods from same marine 350.|
|10-12-2012 08:30 AM|
Like "882", there are more than one "624" (as others have already said). One is the "light" casting, the other, "heavy". Flow from either is not real good... But the heavy castings are pretty tough.
To identify, the "light" casting has scalloped areas along the lower edge where the bottom row of head bolts "live". The "heavy" casting will have no scallops, and probably a single "notch" with a long "straight edge" where the lower row of bolts are.
|10-11-2012 11:09 PM|
What is the complete casting number under valve cover.
462624 is open chamber 76cc low perf crap cracks bad ports like light weight 882 some have tiny valves too.
Some have 2.02x 160 valves but still crap. no power.
Marine version may or may not have hardened exhaust seat insert.
Check for cracks before investing $$$
If you want power find a better cylinder head.
"624" on underside intake runner is a 305 head much like a 4416 head.
small 58ish cc chamber 1.94x 1.50 valve. needs porting and larger valves for a 350.
|10-11-2012 08:27 PM|
|BOBCRMAN@aol.com||624 castings are in general, the worst heads that GM made. Average flow, but VERY crack prone. Later hd versions have a diamond shape cast on the outer side. They are less prone to cracking..|
|10-11-2012 07:51 PM|
|vinniekq2||for what application? for marine,yes|
|10-11-2012 07:14 PM|
82 624 marine heads, any good?