squick

I've got a set of BBC oval port vortec heads that just came off my motor that I will let go CHEAP! They came out of a fresh water only boat and only have ~140 hours on them. They are in great shape. Drop me an email if interested. [email protected]

Stormrider

I've got 4bolt mains w/ rectangular port heads and rebuilding now.
Decided to go to 500HP. Builder says no problem. Very reliable. Will just be a bit more lopey at idle. Gotta go w/ a good exhaust system though!

Crazyhorse

People have been having good luck with the Merlin oval-port heads as well as the stock GM rectangle-port heads. 9.5:1 compression is what I shoot for in the 454's we've done here. The SpeedPro piston L2465F is what I've used in the past but I wasn't impressed with the last set I put in a motor. I'd buy SRP or JE for the next ones.

Prater

Thanks for the help so far guys. I am scavanging for parts right now. Looks like plans are to keep the motor around 5500RPM max. I can use oval ports at that rpm range. Anybody have pros or cons with the oval ports other than they run out of air over 6000 rpm without lots of porting? How are the Vortec heads that 2quick is offering? What intake and cam would work well with that design to get the goal HP. I will not go over 9.5 to 1 on the pistons to keep the fuel requirements down.

Steven

Crazyhorse

The Merlin heads that we've been using in the 330 buildups have ended up with a chamber volume if 117cc, making the compression ratio a little higher than the 9.5 advertised in the SpeedPro book. The guys have all been running them on 89 octane fuel with timing set at 32 degrees total advance.
It's been said on this board that the GM 049 oval-port heads work very well below 5500 but I don't have any experience with those heads. I think Formula31 has the 049 heads.

formula31

Correct. Ive been spining my 049 and 781 ovals to 5400 easily. This year I zero decked the blocks so they will be up a little and I might have to have my props treaked. We'll see. I use the L2399F pistons which are a little lower in compression as I am at the mercy of marina fuel.

WAGS382

Prater,
I have 2 sets of 088 rect port gm heads and 2 hp 500 roller cams if you are interested. These parts are from fresh water with 275 hrs on them and are in excellent condition. The heads have manley extreme duty vavles (inconnel exhaust), 2.250 intake and 1.880 exhaust and have rocker arm studs, guide plates, springs, retainers and locks. These parts supported 530 hp at 5400 rpm with 502 cid. Jeff

Crazyhorse

Wags382, do you have lifters with the cams? Price?

Big Block Billy

I ran 781's to 5800 rpm. I had a machine shop mill a set of 2349 pistons to about 9.5-1 compression. If you use the 2399 they will make 8.9-1 or so. with 119cc heads.
I used a 2 bolt with arp studs, formula 31 is right.
It ran strong for 2 seasons until I fried it (bad seawater pump) I would use a forged crank if you are going to rev in the 5000rpm neighborhood ! Arp 3/8 bolts in the rods are ok.
7/16 rods are better though. Above all else get it all balanced at a good shop. I've used the 049 heads too. A pocket porting job and gasket matching along with the 2.19 + 1.88 valves, and smoothing out the short side radius onder the valve seats really will wake up a motor. One of the biggest things holding these engines back is exhaust. If you can , get the best manifolds or headers you can afford. They will really help make power. BBB

US1 Fountain

iTrader: (1)

Aren't some of the heads not interchangable do to the water jackets: Mk4 vs. Gen 5? Just so you don't pick up some heads and have them worked over only to find out they don't match up to your blocks.