I have a 1977 F150 short box 4x4 with the 300 I6 and 4 speed manual trans. I was considering adding the Clifford intake, Weber 38 2 brl carb, headers, X pipe and dual exhaust combo. I may even add the cam recommended by Clifford as well, or in the future. Has anyone added these items to there rig? I would like some feedback as to whether it is a good combo, and if the gains are as great as stated by Clifford Performance.

Thanks!

 

I'd like to know too because I'm lookin at the same stuff besides the carb

 

Not vendor bashing, but you can get all the parts elsewhere at a cheaper price and better customer service. Unless they've changed in the last year.
F-250 Restorer should jump in with some alternatives for you.

 

Clifford is very expensive. After reading on another forum of a guy who installed the Cliff. cam, and could not figure out why it kept eating bearings, I will not use their products. The cam in question had not been polished on the journal surfaces. The web is full of stories like that.

I would say, buy the cliffy intake used on ebay, or craigslist, or an offy C or DP. Go with a Comp cams 260, or the 268 if you want it to sound camy. Get a good 4v carb used and rebuild it. You'll get better mpg and performance with a 4v. Also, go with the hedman header and good exhaust. With the money you saved by not going thru Cliff, put that money into the head, where you'll pick up most of your gains. Port it, with a good 3 angle v. job, 30 degree back cut on the intakes, and you'll be amazed. If you want to go a step further, have the over-size valves installed, 1.94 intakes, and 1.60 exhaust. Get your valves from SI valves ONLY. Shave the head to bump compression.

 

It always pains me to hear that one of the few companies purely dedicated to straight six performance has let their standards slip (especially when their parts are so expensive), but I've never heard anything otherwise, and haven't had the best luck myself.

F-250 has a great bit of info there on which direction you should head with your build. You can also use manifolds from an EFI truck to save some money yet over headers (if you're so inclined.) The Mr. Gasket #260 is also recommended for an intake/exhaust gasket.

 

Great info, big thanks! I will take your suggestions re head and cam, and I will go with the Offy DP and 390 CFM 4v carb. Headman doesn't make headers to fit a 4x4, only 2wd, so I will need to find another brand, go with Clifford headers or use EFI manifolds providing they fit with the Offy intake installed. I do have a concern re heat for the carb, as the stock setup uses heat from the exhaust manifold via bolting together. Clifford remedies this by having a water jacket built into their intake. I live in Western Canada so I think this heat may be important.

 

The Offy Intake/390 works great with the EFI's.



As for carb heat, that's a very common discussion around here, and there's more than likely a few ongoing threads on the topic right on the front page.

You'll most likely need to run a coolant plate underneath the intake, or a coolant heated spacer underneath the carb, or both. If you look, you can see the coolant lines coming in and out of the spacer under my carb.

 

Thanks for the info and pics. Can you supply some info about the heat plate you're using, so I can get my hands on one?

If I go with the Offy intake, 4v carb and headers, will I need to do the head and cam in order for this setup to work properly? the reason I ask, is I would like to install this setup on the 300 I have in my truck now, While I rebuild build my spare 300 over winter.

 

My 300 currently only has external mods (ie. intake/exhaust/carb) and it works great.

The cam and head-work are on my to-do list, and will be some awesome icing on the cake. However, the gains I've experienced with just the bolt-ons is amazing. Definitely don't need to do a cam and port and polish at all, but they're great for bringing everything together.


As for the heated plate, they're on Ebay from time to time. I usually do a search for "carb spacer" and then click "used". They're easy to spot since they have a tell-tale in and out coolant pipe in the picture.

 

with the headers you will have to do a bit of mod's to all the washer's and prob the alt. bracket not sure on the 77 but that info is here.(header flanges are thiner than the offy ones)


The efi manifolds are just about the same as shorty headers as far as cubic inch opening goes and no mods should be needed for a direct bolt up 99% of the time, might have to fab a washer to span a tab thats a bit off, i didn't have to. my none EFI '86 came with the efi head the 2 extra hole's made for an easy install tho but still no biggy on the pre EFI heads.

i got my OEM manifold's off ebay for like 100? but prob cheaper at a pick and pull, but from what i have read it's a huge pitty to get the dooner parts off??

walker Y-pipe is what most use with this setup, just make sure the open'n for the back manifold is cleaned up as most seem to need a little help there.

from my research here it seems the head is the biggest set back on this moter and needs to be sorted proper if you want the upgrades to even work right.

P&P ran me $40 a hole but can be done if your handy and have air tools to work with, tons of vids on Utube, guy that did mine builds the 300 for dirt tracker's and said a gain of 50 HP.... most will agree I think that ,that number might be a bit high . does let that holly 390 flow proper if ya not after a race truck then I would just start with the P&P and intake valve's back cut 30*, that ran me $90 there

as for heat.... seems the heated plate is all that is needed down to 0*F as I just asked about this with winter coming on here.

I also went with the D.U.I. dizzy with there claim of up to 20 HP gain??? engine has to be tuned around it tho but not a issue really, set the plugs at .055 and timing at 12* and off ya go with a 1 wire hook up


the holly will need setup proper as well but plenty here to help on that and there web site covers it also, just follow the steps to take and do one at a time and test then adjust if need be and go to next... so far only thing I have done is change the power valve to 8.5 as my ported vacuum is 17

The Mr. Gasket #260 is the way to go as AB said as well, has been talked about alot here and it does hold up. just retorque after heated good.


just tossed another pic up like AB's to just show a different angle of this setup and how the parts fit and look.


gotta say tho the way I'm setup now is like madness off road and on the highway like a V8 was droped in it.

some time this winter I'm gonna do the chebby intake conversion which is about the same thing a cam would do but cheaper/easier iirc


hope all goes well for ya

 

Lots of info, awesome! I'm not familiar with the chebby intake conversion?? Also, it seems most guys are going with the Y pipe instead of running dual exhaust all the way back with an X pipe. Is there not enough to gain to justify the duals?

 

you would most likely need to down size with dual's from the walker Y-pipe.... seems to be a bit to much with dual 2.5" out the back but some do run it that way 2" and have good results.

i went 4 foot past the walker pipe and put my flow master on and called it good.... dang happy so far and all 2.5" more than enough IMHO


the chebby intake conversion raise's the lift from 1.6 to 1.7 kinda like what a cam would do.

IMO 2.5" single out is plenty and the intake should be looked at first.... them big ole pistons will push a ton of spent fuel gas out just need to feed them some.... gonna go from a 180cfm carb to a 390 and from 1 7/8 exhaust to at least 2.5 which is double on both ends so need to open the head and intake side of things and wake that 300 up

 

Fixed it for ya.


Yeah, a lot of people switch the rocker arms out for rockers from a Chevy I6. The 292 I believe. It simulates adding a cam. Plus, Chevy rocker arms are like a 1/3 the cost of the 300 ones.

 

ya that looks better AB.... at least I got the lift part right buddy iirc the 292 one's will work just fine


valve side pic of my P&P

 

It is the Chevy 250 rockers. You need the slotted p.rod holes in the head though, because it brings the p.rod closer to rockers, and rubbing is never good.

For about $50 more you can convert to bbc roller rockers. But to do that you need to install screw-in studs with 7/16 shaft. That is unless you find a set like mine for a 409. But then you'll want a transparent v.cover. I really believe someone should make them, allowing you to immediately see any problems, and of course to brag about your rollers!!

Ah, I got to flash 'em.



I guess I would say that if you are going to do a cam, and possibly with the 1.7 chevy rockers, you might want to think about have screw-in studs installed. The push-in type have been know to pull out.