I am interested in getting a new high performance throttle body and a nice spacer to go with it and was wondering if any of you have put on new throttle bodies, lightweight w/bigger throat or not, and a spacer. What was the product that you used and how much was it?, w/o shop fees. Also, if you did do this did you notice any difference in acceleration or top end or engine temp or gas milage or whatever, any improvements need not be left out. I saw this 1" or 1 1/2" cyclone spacer at my work and they boasted, with a dyno graph none the less, that they got improvements of 20 horses, I wish!

 

At one point in time I was gonna upgrade to a larger throttle body and spacer and I give a company a call about it cannot remember their name but they seemed honest and here is why. I was amazed at finding something for the efi 300 and was ready to drop cash and the man says if I were you I would not spend the money. After I learned more and more about this motor I also came to this conclusion myself. Unless you are gonna build this thing for all out racing this is not something you need. They say this motor has or needs more air, open it up, yet from all my searching the stock intake is good for 300hp with the 150 you have now you have a ways to go so this upgrade is not necessary unless you got the doe and could care less who gets it. Something I would recommend would be a ignition upgrade (Msd or jacobs have not used jacobs but have used Msd on BB high compression carbed engines and it starts the first time everytime) and on your efi it should improve mpg and slightly throttle response. The one thing I wish I had done so far is change the cam think about it this is the mechanical brains of the whole operation it controls what your valves do and when they do it which is what the whole combustion process is based on. Something else would be injectors, swap in 19lbs v-8 injectors and a adjustable fuel pressure regulator and gauge and from what I have read a lot of people have been happy with this upgrade as well as the cam. Look up venom-performance.com they have injectors and fuel pumps and a module as well as a 180hp shot of nitros system to bring that beast alive. This is more expensive but you would not have to fabricate anything for these injectors. Do not take my word for it but if I were to do anything for the six as far as upgrade it would be the injectors and cam. The rest would not give you what you are looking for I would not think. Trying to save you some time and money I wish someone would have told me this a long time ago. Been there done that. Good luck hope everything works out

 

I don't have the measurements to hand, but the 302 and 351 T/B are slightly larger (in MM increments), and are a direct bolt-on.

That's the good news.

Here's the bad news:

I've read this, not done it myself: Plan on heliarcing plenty of material to the T/B flange/plenum joint, as the material from the factory is too thin to bore out to the larger sizes.

Eddie

 

Eddie,
I've not laid it out yet, but I'll bet you could mill out a spacer with a pair of angled conical transtoins to adapt the 302 T/B to the 300 MF with no mods required to either part.

 

Perhaps the conical adaptor is the better idea--there would be a net increase in CFM over the 4.9L T/B, and the venturi effect created by the smaller diameter on the downstream side would maintain flow velocity for low end.

I wonder if the larger T/B and conical-section adaptor might not be the perfect accompaniment to the larger injectors?

I wonder if both mods might not be enhanced by a third and fourth mod--3, a rocker with a bigger ratio for more lift on the stock cam, and a 2.5-3.0 inch spacer between upper and lower intake manifolds?

Oh, and SR: what was the P/N from Summit for that direct-fit hi-flo Catco you got?

Ed

 

Didn't get it from Summit, used a local exhaust shop that does custom work. They didn't give me a P/N.

 

Eddie,
I'm thinking about that 3" spacer, and I've got my doubts. The 300 is already manifolded for low revs, lengthening the runners by 3" lowers the "tuned" torque peak even further. If you're building the engine, you're going to want to add some mid-range to upper end performance, so more runner length is something you don't need.

I know there's the clearance problem with the Clifford valve cover which is required by the roller rockers, etc. But do you really need 3"? I should think that in this case less may be more (engineers can quote von Mieses too). If there's any excess meat on the bottom side of the upper plenum, you may want to attack that for clearance as well. If you can get that spacer down to 1"-1.5" you may want to consider phenolic to give you a heat barrier between the upper and lower manifolds, there's a couple of HP to be had right there.

The whole T/B plus conical adaptor thing is going to add at least an inch, probably more, although I'm not sure about the effects of adding length upstream of the plenum. The tractor motor could easily end up being just that if you're not careful. The real killer is that the bigger T/B is only going to be required if you spin the engine harder and cam it up a bunch, both contrary concepts to increased runner length. Ford did too good a job of engineering the manifolds for the 300

 

Yeah--Ford's value engineers left us precious little excess metal to work wonders with!

Actually, my first thought on seeing the revamped 4.9L in late '86 was "Best thing Ford ever did, hanging EFI off the 300"

I'm not sure how thick the spacer is going to be; I need to get that valve cover first for a exact distance. I'm planning on milling off the finning on the cover, so there is that height
reduction. That spacer may be a moot point anyway; I don't think runner length makes any difference to a supercharged engine anyway (should I decide to do so).

Guess I get to reread Phillip H. Smith again...

Eddie

 

[QUOTE
Guess I get to reread Phillip H. Smith again...

Eddie[/QUOTE]

I already checked, nothing in there about the effects of overpressure on ram length or vice versa.

 

I doubt intake tract length makes any difference with a positive displacement, constant pressure blower.

Look at all those nasty 5.0s running miles of discharge tubing.

I would probably want to "O"-ring the upper/lower joint and probably the manifold/head joint, too.

Eddie