320 efi heads
 

does anyone know what heads came on the 88 320 efi engines I seized one of the engines 2 weeks ago and I'm pulling both engines and plan on bulding 383s and going to carbs just wondering if I need to price in new heads in the build. The engines are being pulled out in the next week or so.

Fixx
 

what year? most likely the heads are fine,get the casting #s and go to mortech.com and look them up..their could be several differant style of heads used..

the motors are 88s so I wasn't sure if they were vortec heads or not the motors should be out by they end of the week I'm looking to get around 400hp and hope that they will work so I don't have to spend the extra money on heads

They're center-bolt heads, but in those years they won't be Vortech's, unless someone upgraded to them. Are you planning on re-using the EFI assemblies in your build? If so, keep us updated. I've entertained upgrading my 320 EFI's for more power, but would like to keep the fuel-injection.

I'm not going to use the efi I think that's why the motor seized so I'm going to carbs

Let me know if you want to sell them then. I could use a couple spares for parts!

Ok the motors will hopefully be out this week so I can start tearing them down

Why do you think the EFI caused you motor problems... I have an 87 320 EFI and am currently having issues with it as well, but it has been sitting for 2+ years. The problem i am having is it fairly often falls flat when you first try to accelerate and occasionally pops back through the manifold. On 2 occasions I even had to throw it in neutral, clear it out, and then put it back in gear and it would run. Tried the basic tune up stuff, plugs, wires, cap, and rotor last week but if anything it was worse. Last time out it would not turn over 4000 rpms (compared to right at 5000 when i first got it back in the water a few weeks ago and 5200 before it sat). I am sort of hoping it is just old gas, but i have added fuel twice now and it does not seem to be getting any better.

Mine was acting up all year like that somedays it would run fine but didn't like being over 5000 and the day it seized it was running fine and then 1 motor just started losing rpm slowly and finally quit plenty of oil good oil pressure but the motor locked up completely so I don't want to chance doing it again, and since I plan on strokers anyways it'll just be easier to tune it with carbs. I bought the boat as a repo and it sat for a long time similar to yours

Thanks... I am hoping it is just bad gas, but it does worry me that it could be a bad injector, loosing fuel pressure, or something like that causing a lean condition which could destroy my motor. The previous owner had actually had the motor pulled out in 1995 and sent off to a place that specialized in marine engines (drawing a blank on the name) and they completely went through the motor, forged pistons, rod bolts, decked, balanced, and they added a set of Dart iron heads and a Crane cam and then dyno'd it (with headers). It made right at 400 HP and then they replaced the ECU (not sure if they added any custom tuning or not but they did have the specifics on the spark advance) and then it made 424 HP (all with the 320 EFI injection setup). I really hate the idea of back stepping back to a carb, but the lack of parts and the difficulty diagnosing problems with this EFI does have me considering it. I would really like to switch to that new Edelbrock EFI, but that cost 1/3 the cost of the boat.

yeah I don't think mine have ever been apart and have 480 hrs I would like to stick with efi but the new kits are pricey so I'm just going to go with carbs for now but I do really like the fast system

Replace your merc ECUs with GM speed density units.

These guys can help you with the swap, http://tpis.com/

You will love the way it runs!

Jeff

did you do this swap and how much is involved with tuning it

I did something similar, I changed from a carb and used a 320 lower manifold(didn't have the upper). Made a custom upper with an LS1 throttle body. I had to make an adapter plate for the exhaust to fit O2 sensor. I dynoed the engine on their dyno, they did the tuning at that time.
If you give them the engine specs they should be able to burn you a PROM and get it right on. I can send pics to your e mail if you would like.

Jeff

that would be great my email is [email protected]

I am also thinking what will be the appropriate head in my engine which is the same as yours. I am hoping to see some photos here. :D

I would also appreciate any pictures or info you could send me. I continue to have problems with mine. It did seem to get better yesterday and it is still possible that the old gas may be my primary problem, but it was still down about 400 RPM at WOT and about 4 mph. I pulled the connector to the MAP sensor and it made no change. Almost seemed to run better for a bit and then started messing up again. Thanks, my email is: "[email protected]".