I have a '76 F250 camper special with a 360 in it. A friend gave me a good holley 650 and I'd like to run it on the original manifold until I can afford a 4bbl manifold. I have an adapter plate. On the stock setup there is a piece between the carb and the manifold, with an exhaust port and a vacuum port in it. The power brake vacuum hooks to this. I assume the exhaust is to help warm the engine. Should I leave it in there? Or should I forget it and put the 2bbl back on? If I pull the stock "adapter" out then the new adapter blocks off that exhaust port. Is that a problem? Thanks!

 

In this spacer, is there any way for the exhaust gases to actually get into the intake stream? If so, you should probably leave it alone. That's the EGR smog control system. You may have trouble getting your truck smogged. Here in CA they're really tight about that stuff. If it's not, lose the spacer and convert the adapter to add a vacuum port. You'll need to drill and tap the adapter plate with 1/4" NPT threads and install a hose fitting that fits the tube that goes to the brake booster.

I'd encourage you to wait for the 4BBL manifold. Even then, from what I've heard all over this forum, 650 would be WAY too much carb for a stock motor, especially if you're running the stock cam designed for a 2BBL carb. A 650 would only be useful on a motor that was set up for it from the ground up.

When I bought my truck, it had a 390 with a 650 cfm carb and an Edelbrock Streetmaster single plane manifold. Otherwise the motor was stock underneath. It ran crummy and had no poop until I replaced the manifold with a stock ford dual plane, put a 600 cfm carb AND installed a nice mild Crower 250-HDP RV cam, designed to take advantage of that 4BBL carb. It's a real stump puller now! Gobs of power, but still quite dreveable.

If you don't want to replace the cam, trade that 650 for a 600, put in really small jets, and find a nice cheap used dual plane manifold. You'll be much more satisfied with that setup.

Oh yeah, how many miles are on this engine? If it's more than 70 or 80k, the added horsepower can cause the rings to go.

I hope this info helps.
Good luck.

 

Where do you live and how is your back, I have a stock ford 4bbl manifold that was on my 390 with an adapter to run a 2bbl Holley. I bought an Edelbrock aluminum manifold so the original is just sitting in the rain in my back yard (Seattle WA) It's a heavy s.o.b. I'm told that stock 4bbl iron manifolds aren't particularly expensive

 

Hey BBT, How'd your truck run with that 2BBL carb on the 4BBL motor? What was the advantage? Was it mileage?

I had a '63 T-Bird that had a 390 with a six-pack and though it wasn't as fast, it was a lot more driveable around town when I disconnected the linkage to the outer 2 carbs. I sure wish I had that set-up on my truck now!

Don, BBT is right on about the fact that the iron FE manifolds are HEA-VY. If I had it to do all over, I would have gone with an aluminum intake. The weight savings make it almost worth it.

Jimbo
<a href="https://www.ford-trucks.com/pictorial/big/1976_f250_2.html">https://www.ford-trucks.com/pictorial/big/1976_f250_2.html</a>

 

I can't say how the 2v holley works because almost immediately I replaced the whole top end of the motor. I've recycled the edelbrock 600cfm 4v that I had for a year on my other truck (302-crank went bad). Before I did that I had bad exhaust leaks, a broken pushrod, brocken rocker arm shaft, cam with some flat lobes, and GT heads that had 8 bad exhaust valves and seats. Now I have fresh heads (not Gt), a comp cams 268RV cam, new dual exhaust (stock manifolds 2" pipes) and edelbrock performer 390 manifold w/ 600cfm performer carb and crane electronic ignition. I need to so some tweaking on the carburation (secondaries too rich) and it need a clutch pretty badly but it seems to me to have decent power. I don't have a big history with these trucks, only a 76 that I converted from 300 to (doomed) 302, so I can't really say how much improvement this all made. I get a little bit more rocker and valvetrain noise than I was hoping for but I've been told by some others that that goes with the territory with an FE. It compares favorably with my bandmates 84 chev van with transplanted 90 gen2 350. I know that I felt it (the chev 350)was clearly more powerful than my 302 had been. I don't feel that way now (with my 390) and matter of fact I beat him up the steep grade to my house (he backed off due to pinging). I wish I had gone with bigger exhaust, I have 2-1/4" duals on my 76 with ProFlow mufflers and it made the 302 sound much tougher than this exhaust shop job with turbo mufflers. I had a little rear end accident that busted a steel brake line a little over a week ago so it's been parked while I fix that. I got the side tank out and replaced the broken section of line today and I plan to bleed tommorrow so that I can get back to driving it.

 

BTW I just bought the truck in sept, so again, I only drove the truck with the holley for about 20 miles, to get it to my house.

 

Yeah, I suspected after I got it apart that this is not the way to go. The engine has about 96K on it, Id like to get another 40. The adapter does not have the exhaust tied to the intake, the PCV is at another vacuum line. Out here I dont have to go through DEQ anyway. I'll just get the stock gaskets for it and put it back together.

Thanks!

 

...and got a lot more low end torque. I was running hooker headers with dual 2-1/2s through turbos. It turns out that I didn't have enough back pressure. I went to dual 2s into a muffler with a single 3" ouptut which made a big improvement.

 

I just took my stock intake manifold off my 360 and swapped it with and edelbrock. Now I dont know about running 650cfm off it.... maybe 600, but all the same if you want a 360 intake manifold that is in good shape for free... contact me. I ran a 4 barrel 600cfm off it and it ran like a champ. So if your lookin for cheap, and want to deal with gettin it... I would have no problem giving it up to someone that could use it.
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