Can I marinize a Q-Jet?

[racinrc14]

Ok, so here's the deal: I have an '83 Cobalt with the Merc. 898 (Chevy 305). It currently has a rochester 2-barrel on it. I have recently replaced the drive with a new SEI 106(I love it, by the way!) and now that I have a solid drive, I would like a little more zip out of the hole. In my shop, I have an old Quadrajet (and intake) that came off a '86 Chevy Blazer with a 350. It was an older, non-centerbolt, small block arrangement. Assuming it would all bolt right on, is there a kit or anything like that I could use to marinize the carb to make it legal for marine use? Thanks,

-Tommy

 

[jtmarten]

Re: Can I marinize a Q-Jet?

Would probably be more work and money than just buying a new Edelbrock or Holley marine carb. The Holleys have different overflow tubes, and additional seals in the baseplate, not sure about the Q-Jets.

 

[180shabah]

Re: Can I marinize a Q-Jet?

unless your doing a head swap on that old 305, I wouldn't bother with the 4bbl. Do you still have that 350?

 

[racinrc14]

Re: Can I marinize a Q-Jet?

I do have the 350, but the block is a mess. The Blazer it was in was wrecked, and when that happened, it broke out one of the front mounting lugs. Also, when disassembling it, my ridge reamer cut a groove in one of the upper cylinders and I'm not sure there's enough material left to clean it up. Besides, I'm not sure an engine swap is what I really want to tackle right before boating season! I suppose I'll live with it 'till something else pops up. The 350 heads would bolt on, wouldn't they?

 

[180shabah]

Re: Can I marinize a Q-Jet?

I was thinking morealongthelines of use the boat as is, and build the 350 in the off hours, not doing the swap 'till winter.

As for heads, don't swap for the 350 heads, you are limited by the small bore diameterof the 305, and the "design" of the heads from that era. Swapping in vortec heads + intake and 4bbl would make a HUGE power increase. I still think a 350, with or without vortecs, would be a better choice.

 

[zbnutcase]

Re: Can I marinize a Q-Jet?

Dont even think about using that '86 carb as it is way too new and emission controlled for marine use. Use #1409 Edelbrock carb instead.

 

[racinrc14]

Re: Can I marinize a Q-Jet?

Food for thought. Thanks guys,

-Tommy

 

[ken_23434]

Re: Can I marinize a Q-Jet?

What you end up getting with 350 heads on the 305 is a situation where the combustion chamber in the head is a larger diameter than the 305's bore.

Even though you might get a better shaped/design of combustion chamber, larger valves etc.. that you think will make the head flow better and make more HP, likely you will get lower.

As the air flows through the valve and along the edge of the combustion chamber it hits a "wall" as it encounters the top of the block and has to abruptly change directions to flow into the cylinder. The bore of the 305 is just too small for those heads.