9.4 is ok for compression. But I'd limit boost to 10psi because of the terrible head design holding heat and limiting flow. I know you said it has been worked on, but it's still a barely adequate head. With that compression, you'll limit timing as well.
Typically turbos are easier on an efi engine, but you can turbo a carb. I'd invest in a regular 500cfm Holley and put in the solid floats. If you build a box enclosure for the carb, you will have an easier time tuning the carb for every day driving. If you blow through, it will be trickier. Or buy an expensive blow through carb. Up to you.
This will pull great with 5-6 psi boost. The head design really needs all the help it can get. You'll have a very healthy engine. I say go for it.
What transmission are you thinking.

 

Thank you for your quick response. Im trying to read and research all i can about this. Yea, ive done all i reasonably can with the head, at least its better than stock. I think I will go ahead and get it rebuilt with the 9.4:1 CR just in case I chicken out and decide to keep it naturaly aspirated. Its good to know I can put some mild boost to it though. I still have a lot of reading to do, Im leaning toward a draw through settup with a 6.5 chevy turbo. With my limited knowledge, I think a draw through is more simple and easier to tune being it is old school carb. And the 6.5 may be easier and cheaper to come by than a cummins turbo. You asked about the tranny, its a four speed, NP 435, 4.10 gearing in a 3/4 ton 4x4. Its turning almost 3000 rpm at 65 mph. I still have a lot of research to do, I dont want to ask any "dumb" questions. I may have questions later about building the bottom end.

 

Draw through turbos are built specifically for that, so a 6.5 turbo I doubt will last long.
The thrust bearing is designed for a certain restriction, and a carb is like always having a real dirty air filter, restriction wise. Then, you have surge from the throttle blade in front of the compressor wheel, and also you can't typically run a blow off valve because the air has fuel in it (unless you get real creative). As well as the fuel in the air can erode the compressor wheel.
Still thinking about draw through.
Find a turbo from a 4.9 turbo trans am. It will be tricky, but well worth it in the end. It was designed for draw through.
Some draw through kits I've seen had elaborate carb plenums and flaps and diverter connections. Keep searching.
The issue with the gm 6.5 turbo is that it's kinda small. I use bigger turbos than that on my 2liter cars I build. It will work, but I had two of them lined up to go on my 5liter mustang, and decided they weren't enough. Probably enough for 10psi on a lower reving engine though. I gotta look up their airflow again.
See if you can find a zf 5speed for your truck. The 4spd is a killer. 3k at 65 is more than I'd be happy with.
Don't go too big of a cam. You can put a healthy one in, but nothing with a lopey idle.

 

Thanks for the info, thats news to me about types of draw through turbos. Ill have to do some more research on that. Yes, I have thought of the zf5 speed. The NP 435 will stay for now, but I agree the gearing will be much better with a five speed and over drive. (Later project) So far I am planning a mostly stock bottom end build with the addition of cast iron timing gears, High flow oil pump, and some sort of a mild rv cam. CR target is 9.4:1. Do I need to consider a better than stock piston, or will stock pistons be ok for mild boost?

 

Better pistons allow for more boost, but better pistons will be better under extreme conditions. But think of this, cast pistons last very well for being stock. If you're staying under 10psi and you have good tuning, stock cast will be fine.

 

This is all good news to me, I think ill go ahead and build the bottom end this winter and in the spring, go ahead with plans for the turbo. If i chicken out on the turbo, at least i will have a strong NA engine.

 

Just to add isult to injury, but the earlier speed density ford efi's were batch fired with 2 banks of 3 injectors.

I would upgrade to the '96 EFI or rip out the harness and install an after market EFI, like VEMS. (VEMS USA)... Hardest part about going aftermarket is triggering

 

I found a Ford 6.0L turbo (pn: 1854593c91 which is GT3782VA I think ) at the DUMP! As for the Control of the Vanes, it's PWM'd AFAIK and found this forum about it. Going to use VEMS' secondary PWM control for it...

Would this be a decent size turbo for the 4.9L?

 

Not sure who's truck you're talking about guys, but Sams truck is already mass air most likely because it's a 96, and mightymouse's truck is a 67 and is carbd...

Zark, that turbo is way more than you need and has a big exhaust housing. The variable vane is helpful though if you can actually control it. The forum page you posted was pretty vague, but may get you in the ballpark if you're good at figuring stuff out. I was tempted to try the 6liter turbo with my megasquirt setup on my 5liter mustang, but at the time, my electrical engineer buddies couldn't figure it out with the info available. And it was about the same time as that forum page was written. Maybe earlier. But we couldn't find any info on it so I passed and went with a different turbo.
Anyway, the turbo is plenty big, probably bigger than you need, but if you can figure out the variable vane control it should be fairly responsive. You'll still need a wastegate, and then set the pwm controller up with a boost reference so that it's not trying to crank the boost out when the wg is open.

 

Thanks for the answer to my Thread Hijack!

When things are more firm in my head as to what I'm doing, I'll post a new topic. As for the 6.0L turbo, it was free! So unless I locate another freebie at the dump, I might push it into service after a rebuild. AFAIK, the vanes are controlled by PWM @ 3.3KHz but my VEMS only goes up to like 600Hz so hopfully it'll still work. As for the MAP, it is done by KPa to RPM.

 

Yeah, you're slightly inadequate with your pwm.
Keep looking for solutions. I really like mega squirt. I have it on at least 10 vehicles.
I don't remember what the PWM output of megasquirt is, but it controls a fair amount of stuff. I think I know of a guy who makes a standalone controller that does a lot of stuff that may be able to help us with this project.

 

So what happened?

 

I chickened out and built a regular boring N/A engine. A turbo setup goes against my requirements of simplicity and reliability. Its a daily driver, so I had to do something to get it back on the road in fairly short order. With that being said my 300 isn't a "regular" rebuild. I did a lot of cool stuff including high compression, 3 angle valve job, porting the heads, cam, as well as all the regular high performance bolt on stuff. The engine makes great power, very comparable to a medium cubic inch v8 engine. A turbo setup is still very fascinating to me, but for now ill leave it to the guys with a little more knowledge and a bit bigger pocket book.

 

What did you end up doing overall? I have the 95 version of your truck, without MAF

 

I was recently looking through some of my old magazines and it the winter 1995 edition of Ford Truckin' there is an article on the E4OD trans and at the time of publication there was a company in CA called Premier Performance Transmissions that sold a standalone computer for the trans. Being that the issue was over 20years ago I have no idea if the company is still in business, they listed their address in Placentia, CA and phone (714) 630-3235.