Fuelie heads

[85diplomat]

Just bought a set of Double hump/ Fuelie heads.2.02\1.60 valves. Will these work better than the stock heads on my 305 mercruiser?( other mods include flat top pistons, 262 extreme marine Comp cam,air gap intake, 600 cfm edelbrock) The purchase also included a set of double valve springs,and screw in valve studs.I also plan on Thru hull exhaust(4"),with(4" stock mercruiser risers)

17'Diplomat I/O sbc 300+hp

 

[85diplomat]

Just bought a set of Double hump/ Fuelie heads.2.02\1.60 valves. Will these work better than the stock heads on my 305 mercruiser?( other mods include flat top pistons, 262 extreme marine Comp cam,air gap intake, 600 cfm edelbrock) The purchase also included a set of double valve springs,and screw in valve studs.I also plan on Thru hull exhaust(4"),with(4" stock mercruiser risers)

17'Diplomat I/O sbc 300+hp

 

[bdusted440]

double hump heads are a good head but are not fuelie heads.I've never seen a set newer than 1972. Fuelie heads started in 85.You need to run the casting numbers to see exactly what you have.IE cumbustion chamber size and shape.And if they are 2.02 heads you wont be able to stick a match book cover between the valves.It's real tight.But if they are true duble humps they will definatly help you're 305 breath.If you're going to run fuelie heads go with ls1 heads there the most eficiant stock heads.just my 2 cents as a gm tech.

CHECKMATE'S AND MOPAR'S GOTA LOVE EM
77 trimate merc150xr6
84 ambasador v8 i/o project

 

[175checkmate]

I agree, run the numbers on the heads to see what you have. The trouble I have ran into in the past is putting 350 heads on a 305 is the drastic drop in compression. The bigger chamber on the 350 heads kill's any gain you would see by the increased breathing ability.

1975 Checkmate Tri-mate 2, 2.4 200+ / Sky jacker 6" plate / 25p Laser 2 prop, Currently the boat is undergoing overhaul.

 

[85diplomat]

"462" heads produced 10/31/66, casting number 3390462, 64 cc combustion chambers. Also have you had experience porting and polishing and can it be done by a DIYer. I have 3 months to work on them before I need to send them to the shop for a valve job and assembly

17'Diplomat I/O sbc 300+hp

 

[JW]

Double hump heads were the hot heads to have back when. Now you need to turn that motor into a 350 or 383!

Checkmates owned: 1995 Pulsare 2100BR/1995 Mercury Promax 225 2.5 EFI. 1995 Persuader 183/4.3 LX V6. 1992 Pulse 171/1992 Mercury XR6 150 hp 2.5 liter.

 

[vinny p.]

I was under the assumption that Fuelie heads had the double hump markings on the front, but had no bolt holes for any accessory mountings. I have also seen this double hump head come with 1.94 valves as well as 2.02. You really need to measure the valves to be sure. In any case, while I am sure that these heads will flow better than your stock heads on the 305, as was stated, you have to make sure what cc the chambers are on both sets of heads. Don't go by what the casting # tells you, these heads have been around for a long time, I would bet that by now, someone has milled them down a little. You have to get the compression right before doing anything else. Once that is done, then a little clean up or de-burring of the ports and bowls will definetly help. Just keep in mind, that just because the heads can flow, doesn't mean you will have better flow through out the induction system, or that the motor even needs it. You have to match the cam , intake and exhaust system. Sounds like you have a good intake, but be careful of the stock Merc. risers. They are not very forgiving when it comes to reversion. You will be very limited to what cam profiles you can run. Ask a few questions to some reputable cam companies before committing yourself to a cam shaft. That 305 has a cast lower end. Be careful as to how much you push it. It is really not designed to add horsepower to it. I like what JW said, only I would not turn that motor into a 350 or 383 stroker, I would build one from scratch.

 

[vinny p.]

bdusted440,
quoted" posted December 28, 2003 12:38 AM
double hump heads are a good head but are not fuelie heads.I've never seen a set newer than 1972. Fuelie heads started in 85 "

I think you are mistaken. Fuelie heads were one of the premier performance head Chevrolet made back in the 60's. Those along with their 292 casting # turbo heads were the heads to have years ago. Since 1985, Chevrolet has made nothing but junk smog heads, with the exception of their Vortec heads.

 

[bdusted440]

You are corect vinny I was thinking of the new style fuelie heads .I didnt even think of those heads as it's been at least a decade since i've seen any .In fuelie heads I was refering to late modle corvete heads.

CHECKMATE'S AND MOPAR'S GOTA LOVE EM
77 trimate merc150xr6
84 ambasador v8 i/o project

 

[85diplomat]

As far as "trading my 305 for a 350 or 383" the boat and outdrive won't handle it nor will my wallet.Also, I did build this one from scratch(my first)and if I can create a 325-350 hp motor for just over a grand, what more can you ask for. My boat's name is Cheap Thrills for a reason. How many 60+ MPH boats can you get for under 2 grand?!?
I have the valves and they are 2.02/1.60 and am headed to the machine shop tomorrow to have the heads speced out. I am interested to see if they have been milled. Besides The compression is only at 8.95:1 so even if they have been milled down to 57ccs I still can run on regular gas at only 9.7:1.

17'Diplomat I/O sbc 300hp + climbing,70MPH or bust

[This message was edited by 85diplomat on December 28, 2003 at 11:42 PM.]

 

[vinny p.]

I don't think you can run regular gas (87 octane) at 9.7 compression. You will at least need to run 93 octane. Good luck in the project. Keep us posted with results.

 

[Tejas Raz]

I'd like to suggest a book for all the IO drivers out there, at least the do-it-yourselfers.

Small-Block Chevy Marine Performance by Dennis Moore. Published by HP Books. You can probably get it at the book store or on www.Amazon.com There is also a Big-Block version.

Other things to think about from the book:
-The larger valves will get you 10-15 hp.
-Get hardened valve seat installed in those old "leaded gas" heads. They've got soft seats.
-They probably don't have accessory holes drilled in the front.
-Pocket Port them and don't worry too much about porting which will cost too much. If you want more power than that, get a set of used Vortec heads and a manifold to match (different mounting hole configuration). Stock, they will beat most other heads that are ported!
-Make sure you measure valve to piston clearances when you shave those heads for the right compression ratio.
-9.0:1 will run 87 octane, but any more and you're into 93 octane. Vortec head design is more tolerant on this too as they mix the gas better.
-Use AC Delco Rapid Fire plugs that have projected tips. Actually any plug that has projected tips help considerably. Just get the appropriate heat range. Marine plugs only add corrosion resistance.
-He doesn't even talk about your 462 heads in the book, but gives detailed info on later heads.

Make sure you stick with a Marine cam with the right overlap and duration timing or you will get into reversion problems, or "sucking" water into the combustion chamber. Bad Juju!

Good luck! Nice to see a lo-buck screamer!
~Scott

1992 Checkmate Persuader 219
"Black Beauty"
350 Magnum / Alpha
http://community.webshots.com/user/tejas_raz