565 cubes 308 or 345 marine heads

[chk259]

looking for someone with marine engine experience especially i/o drive, currently assembling a 565 BBC 10.5 :1 comp , hyd roller 246/246@.050 .630lft 110ls ,h beam rods , 4340 crank etc ,, my guestion is what heads work best ? the machine shop I use also builds alot of engines for various forms of racing but has limited marine experience , they are reccommending the iron eagle 345 head for my application based on the displacement , i have a Brodix HV 2000 intake and a 950 4150 carb that will be used .. whats your thoughts ????

[lun40119]

If it were me, I'd go with the smaller head.........doesn't look like you want to turn it hard judging by the topend and cam you are using. I would look for effiency and throttle response.

Just me though...........and I don't know crap. :D

[want-a-be]

I'd build this for bottom end not high end. This thing is going to want to be ran like a circle track engine. Long and hard across the pond. Unless you are going to be racing,...I would build for top end to be about 5500 rpm.

just an opinion.

Don

[chk259]

If it were me, I'd go with the smaller head.........doesn't look like you want to turn it hard judging by the topend and cam you are using. I would look for effiency and throttle response.

Just me though...........and I don't know crap. :D

kinda what I thought its odd though if ya look at some of the marine engines that are out there they all seem to have either the 325's or 345's i did a 522 years ago and put 269's on it with hv intake "oval"
and it ran great in a 28' velocity pulled hard to 5600, i originally had this as a 555 with 9.5 to one and pro comp 320's with same basic cam and carb and it ran great all the way up untill an exhaust valve broke ha ha ....

[Cboggs]

You're on the right track, .. a head in the 310-335 cc range would be great.
345 is too much I think, . .

Marine applications keep the rpm down,. . I do a bunch of marine stuff
although most of my work is racing based and higher rpm.

Have you thought about Dart's marine aluminum heads?

Curtis