I remember a LONG time ago there was threads about the internals of a 454/365hp mag and what they would support as far as hop ups. Maybe posted by Tyler Crockett?? IIRC they have some pretty good internals stock as opposed to the 330hp version. Anyway i cant seem to find them. As the title suggests can you get 500 out of a 365 mag? maybe even a little more? I have two of them in my 31 Scarab thx

Quoting myself from years ago:

I have a pair of blowers that would get you there, I'd even sell the complete engines.

Cam, Springs, Intake, Carb and Exhaust, Good Tune, Easy.

540 hp from 468 with cleaned up rectangle port chevy heads, 9.75 compression, air gap intake, performance cam, 850 Holley

Here's a link for you. This is just one combination that gets you there.

How do aluminum heads hold up on a fresh water but non-closed loop cooling system? My Gen 6 502 is at the machine shop now being brought to a 509 and I don't know if I am to ditch the stock iron rect port heads for Aluminum or have them cleaned up. I am looking for 550ish, it is a Mag MPI but a MEFI 1 so I am ditching it for a Holley multi-port TB injection setup.

I was going to go alum heads. Looked very positive to me to run at LOTO. By the time I had the blocks bored, new pistons, decking etc, the budget was blown for the alum heads. Heads were cleaned, 3 angle grind on the valves, new springs, seals, seats cut. Makes plenty of HP & TQ for me. Head work 800.00 vs XXXX.XX

Personally I'm hoping they hold up great!! This upcoming season will by my first on AFR aluminum heads. I don't have closed cooling either but boat only in fresh water. I did have them "Hard Anodized" because AFR suggested it for marine use but I guess that is only necessary if you boat in salt water. I did not know that at the time.

If you don't mind me asking what the cost for a set of those are? As Helmwurst stated I too am working on a budget and want it up and running for late may/early June including testing which I know is 20 weeks away but I think I will need all 20 and then some with the way parts are now.
The Holley injection and fuel system alone I'm going to exceed 5K before any engine work.
I am also debating just cleaning up the stock iron heads because again its not a race engine just a healthy lake romper!