Re: 90 7.4L intake manifold
 

Your very likely have a Rochester Quadrajet with is a spreadbore (the carb secondary bores are much larger than the primarys). On Holleys (squarebore), the primarys and secondarys are the same size. The mounting hole locatings are different too.

Re: 90 7.4L intake manifold
 

I have an aluminum Edelbrock "Performer" made for peanut port heads and q-jet spreadbore carb I will sell you. It is in excellent shape, with the center divider cut down about 1 inch. It was used one season, and make 426 HP on the dyno with a 1 inch open spacer. I also have the camshaft and lifters that went with that combo.

Re: 90 7.4L intake manifold
 

what do you mean the center is cut down, and u took a 330hp 7.4L to 426 with a cam and intake???? that doesn't sound right

Re: 90 7.4L intake manifold
 

There is a divider inside the plenum of the manifold where the carb sets. That divider was cut down to make the engine think the plenum is larger. Its an old trick.
The engine was a 330 HP. We installed 2.19 and 1.88 inch valves in the peanut port heads, and just did some minor bowl porting. We added a differnent cam, lifters and springs. Also added roller rockers, which really add very little horspower if any. Did some minor work on the q-jet. I also changed the pistons, went .030 over but keep the stock compression ratio. The engine was completey tore down, align bored, balanced, and carefully reassembled. 426 HP, 502 ft lbs with the peanut heads, on shop headers. EMI's were used in the boat. Infact, I still have those heads, cam and lifters, and intake manifold in my garage.

Re: 90 7.4L intake manifold
 

just curious as to why u ended up parting the engine? I'm new but in the questioning state as far as my engine goes. It's my first boat and i'm trying to learn as much as i can and would like to do a couple of things on a limited budget. I like to spread myself thin with seasonal toys since i'm in wisconsin. Also, what are EMI's. thanks bud

Re: 90 7.4L intake manifold
 

The engine had 550 hours on it. It was running great, we simply wanted to kick it up a notch. When we tore it down for inspection is was in fantastic condition. All we did to the crank was polish up the journels. We replaced the rod bolts with ARP's which is a high quality rod bolt. We changed the pushrods also to 3/8 from the stock 5/16. New timing set and oil pump. Normal things on a engine with that many hours.
EMI's are exhaust manifolds made by Eddie Marine Incorporated. They are an upgrade and improvement on stock merc manifolds, but they are an economy type upgrade. They are not a true header. There are many guys on this board that have done what I have done. Look in the archives.

Re: 90 7.4L intake manifold
 

i wasn't implying that i didn't believe you, i was just wondering what you did. My local boat guy keeps shooting me down when i ask him about minor upgrades to the engine, says i will make it unreliable and blah blah blah. So i'm trying to learn about the available upgrades to the 7.4L on here. You just have the heads and other stuff laying around? Is that stuff i could basically bolt on and go, or is there more to it. I plan on pulling the motor out this coming winter and would like to get a game plan together.

thanks

Re: 90 7.4L intake manifold
 

Yes, those heads are in excellent shape, but they are bare, Valves and springs were used elsewhere. The same engine now has different heads to accomadate a completely different combination. The cam and lifters are still available as is the intake manifold. Send me a private message if you want to talk about it further.

Re: 90 7.4L intake manifold
 

cloudmaster,
Check for flame arrestor clearance before you buy a new intake manifold because you will need several inches to fit any low-medium rise replacement. Stock cast iron manifolds on 7.4's are as flat as they get. I think Weiand also makes a model for your carb/head combo called the Action Plus.

Re: 90 7.4L intake manifold
 

good call, here is the link, just have to find a holley dealer now to find out how much it costs.....

http://www.holley.com/HiOctn/ProdLin...AMSM/8017.html

Would i see any benefits from just adding this manifold, or do i need to put in a cam and lifters to see anything or keep the engine reliable. It looks like my current Rochester carb will fit right on as well.