Originally Posted by powerplayinc

The boat did 55mph with the 330hp 454 in with peanut butter heads in it, so now trying to hit 70 mph is my goal. Thanks

Originally Posted by Scott Foxwell

HP will be about the same, (maybe less) but power under the curve will definitely suffer. VE will be way down with the bigger heads...cyl filling will suffer, and so will tq. as a result.

Originally Posted by Scott Foxwell

Well I don't have to throw a rock in the lake to know it's going to sink. Some things are just obvious...at least to someone who knows what they're talking about (which I understand leaves you out).

Originally Posted by jeffswav

Quit over thinking it, just do what Bob recomends. He is the cam guru. Just get him the information he needs and tell him your goals.

Originally Posted by powerplayinc

Anybody have an idea to what this collaboration of parts might make and or with 320 afr or brodix heads instead of the 305 afr's?? closes ideas, speculations or even off the wall lol ?? The boat did 55mph with the 330hp 454 in with peanut butter heads in it, so now trying to hit 70 mph is my goal. Thanks

Originally Posted by articfriends

Somewhat similar to yours is my base motor my blower motor is built around, 540 with billet rods, 4340 crank, Dart 9.80 block, afr 315 cnc heads and a modified mpi fuel injection. My cam is very close to your 1st cam choice, my motor made 657 hp and 660 something tq but my compression is only 8.2-1. With more compression, a better manifold as long as you pick the right cam and heads 675 hp will be fairly easy. A few guys have built 675-700 hp n/a motors out of 540's on here, a friend of Bob Maderas made 700 plus hp with a fairly large cam BUT in retrospect he has said he wishes he would have went just slightly smaller and had better driveabiility. If you want your cam perfect give Bob a call 585-654-8583, in the end his price for a hyd roller custom spec'd is about the same as what you would pay for a out of a catalog cam anyways plus he is a AFR dealer and can get you your heads for what you'll pay for them most places too unless you are buying used ones, Smitty

Originally Posted by Zone 5

If you would like the correct info on which heads AFR says you should use on what engine size, go to their web site and read everything that they tell you about which heads to use on which engine size. Just as a little bit of advance info, they will tell you that 305's are to be used on 396-502 BB's. In fact they actually tell you that their 315's are for the same size (396-502). So either AFR is wrong, and some guy you never heard of is right, or AFR is right. As AFR has been doing heads since 1970 for people like Grumpy Jenkins and Junior Johnson, I'd stick with what they recommend.

Originally Posted by Scott Foxwell

So what's the difference between a 305 and a 315 and why would you run one over the other if AFR recommends them both for the same range of engine? Answer: you don't know.
You really shouldn't give advice on something you know absolutely nothing about.

Originally Posted by jeffswav

AFR is assuming you are going to spool it up to 6500RPM, in a car engine, this would require bigger heads. Most marine engines are going to run 5500-6k max RPM, so a bigger runner is not needed. I am not a expert, this is what I have been told by the pro's.