Good evening all-Recently purchased a 75 F100 with a 351m in it. Purchased a edelbrock 2171 non egr performer intake and 1406 carb to bolt on and have accessed this site a lot to walk me through it. There is a large hole in the front of the intake that I guess I need to plug. From what I've read on here, an air pump check valve bolts in there if applicable. I do not run this, so I need to plug. Anyone know what size plug I need? The hole measures almost an inch across, maybe 15/16 across. I'm thinking a 3/4 brass plug, but would like some input. Besides this plug, all I have left to do is finishing up installing the fuel pressure regulator before its ready to file up. Any insight is really appreciated!

 

I have that intake and the plug, so will check it out and report back later today. And, I'll include suggestions. But, meanwhile you might tell me what cam you are running and anything else different about the engine. And, have you gotten a different throttle cable bracket?

 

Here's the plug you need. It is a 3/4" pipe plug. Or, you can use a 3/4" pipe nipple and cap.





As for tips, you are quickly going to learn, if you don't already know, that the aftermarket intakes relocate the carb such that the factory throttle bracket won't work. Or, maybe I should say they work but you lose about half of the throttle travel. Here's a link to a post that shows what I've done to get it to fit. Basically, I sawed the bracket in half, bolted the bottom part to the intake and clamped a small piece of strap under it with a c-clamp. Then I attached the other half to the throttle cable and moved it around until it hit the carb's throttle just right - with a bit of slack. Once I had it where I wanted it I clamped that side to the strap, took it off and welded it up.

But, note the part about slack. THAT IS IMPORTANT! My first pass didn't have enough slack and the carb didn't always go back to idle. So I had to bend the bracket a bit to get some slack, but on the next one(s) I do I'll give it 1/8" or so of slack.

And another tip - use guide pins made out of bolts with the heads cut off to get the intake on squarely. Four pins in the corners make a world of difference when installing the intake, especially if the engine is in the vehicle.

Good luck!

 

thanks so much for the info, it is really appreciated. I went ahead and picked up a 3/4 pipe plug on the way home and just like you said, it worked like a charm. That and dialing down the fuel pressure on the regulator I installed (by reading that info on here) were the last two things to finish it up. Runs like a champ! I still have some tinkering to do, but so much happier with it. The previous owner did a rebuild on it at some time, installed headers and a cam (I think) and with the new carb and intake, its got a lot more pep. My tranny kickdown lever bolted right up with the adapter, but I doesn't seem to be kicking down when I step on it. I think I will bolt it up and see if I can make it work out. Lots of info on this sight for the wanna be gear head!

 

Glad you got it going. Such a good feeling!

 

I'm gonna revive this thread a little. I just picked up a used 2171 edelbrock. The runners on it are a lot smaller then the openings on the heads. I was told by another car enthusiast that a lot of manifolds are cast small so engine builders can custom open them to their application. My heads measure 1.39X2.00 and the intake runners are 1.22X1.69 . Is this gonna restrict me? I'm running a stock cam, but I plan on putting headers on. Should I look into opening up the intake?

 

Since the intake passages are smaller than the heads there will be no restriction. Were it the other way around there would be restriction. And the big boys, like Tim, say we shouldn't try to match the intake to the heads as we can cause more harm than good.

 

Running the stock cam profile, I doubt you would notice much if any improvement(other than the MPGs) by opening the intake passages. The smaller intake runners will promote off idle performance, as will the bump-stick. My best advice for this intake is to monitor your plugs.

 

Well I'm going to use a stand up chain, and I'm gonna buy a set of headers. My passenger side exhaust is split. Question is which header diameters to use. Summit has 1 1/2 diameter with 2 1/2 in collector or 1 3/4 tubes with 3in collector. Those are flowtech headers set for RWD truck. Since I'm not going to spin over 5,000rpm I figured the smaller diameter is a better fit. Both sets are the same price

 

. Don't they have 1 5/8" ones? Prolly smallest I would use...