4 barrel gains question

[1968charger]

hi guys!
I tried using the search function but couldn't find anything.. I have a 1968 318 and was wondering if you guys saw any good HP gains by simply just converting it to 4 barrel?
Thxs for any input

 

[WileE]

Am I to assume you just want to put a 4bbl intake on stock heads, exhuast manifolds & single exhaust ? Forget it, don't waste your time.

 

[mitchs66]

My Belvedere's engine is a '73 318 (as far as I know it is stock) and I put an Edlebrock intake and Holley carb on last summer. I wouldn't say any horse power gain, but the engine is alot more responsive, and I've still got 20 mpg out of it with the 4 barrel. I ran Newton to Springfield on Power Tour last year, around 700 miles and averaged 16.9 mpg.

 

[Meep-Meep]

I actually put a Holley 500 CFM 2 BBL with an adapter on my old 318 and noticed a difference, but had I driven it on long trips I would have for sure notices a mileage decrease. My recommendation would be for you to put on a TQ from a late model 360 and call it done. Plus that setup is almost free at swap meets. I did exactly this on my old 68 Barracuda and it ran great and the port mismatch didn't seem to bother anything as far as I knew. Definitely put dual exhaust if you add the 4 BBL.

 

[1968charger]

Am I to assume you just want to put a 4bbl intake on stock heads, exhuast manifolds & single exhaust ? Forget it, don't waste your time.

so to see any real gains I should put headers and dual exhaust as well? or not even at that? or is it the stock heads that set me back?

 

[YY1]

...cam...

 

[shag766]

hi guys!
I tried using the search function but couldn't find anything.. I have a 1968 318 and was wondering if you guys saw any good HP gains by simply just converting it to 4 barrel?
Thxs for any input

simple answer is no. it is all part of a bigger package.

 

[1968charger]

Ok what I got from this is that it will become mostly more efficient. I know I sound like I'm completely new at this but I do know some of the basics. I figured since it was an early 318 car with the higher compression then the newer 318 that it might benefit from the four barrel. i wanted to give the 318 some more power without putting to much money into it because I later wanted to swap it for a 340 when I find one. I really didn't want to mess with the internals. I'm going to put headers and exhaust soon and really haven' decided on the mufflers yet and I also wanted to put an rpm performer Intake with a 600 cfm carburetor to give it some more hp and later I can just swap that stuff over the 340 when I get it. So do you guys think Ill see any good improvements with headers, exhaust, edelbrock rpm performer Intake with the 600 cfm for for now?

 

[Coronet 500]

Sounds good, although that RPM might be a bit much for the 318. I'm ok with the save dough and use it later idea. 600 cfm is perfect, if it's a Holley get a vacum secondary. How about 1.6 rockers to raise the lift and use them on the next engine?

 

[1968charger]

Yeah I know the rpm might be a little to much for the 318 but I was willing to sacrifice that because I think it would be good for the 340 when I swap them later and I dont want to buy two intakes. On the carburetor I was thinking of going with a edelbrock because I heard those were pretty good and required little maintenance. On the rockers.. thats a pretty good idea! thanks! Ill get me some more lift without changing out the cam and Ill just roll it over to the 340.

 

[shag766]

318 hop up

simple answer is no. it is all part of a bigger package.

the summer edition of engine masters has an article in it pertaining to this titled, 318 budget hop up. i have seen a proof copy of the mag cover and this article was on it.

 

[shag766]

reason

the summer edition of engine masters has an article in it pertaining to this titled, 318 budget hop up. i have seen a proof copy of the mag cover and this article was on it.

the reason i seen the proof is it is my engine i had built for me is on the cover. :icon_super:

 

[Cranky]

My first 'small engine' mods were with a 289 Mustang. Torker intake, 600 Holley DP, headers. That was the only changes. The engine was a 2v originally so the compression was lower than a 289 that came with a 4v (Fords term for 2bbl and 4bbl). It woke it big time! An engine is nothing more than an air pump and the more air and fuel you can pump through it, the more power it'll produce but the smaller the engine, the 'smaller' you need to think. Small carbs, cams and headers is key. Yeah, a 4 bbl carb should be part of a larger package and the TQ idea will work very well on a teen even with the stock cam and exhaust but duals should be part of the plan....and a teen will rpm if you let it breathe. It might surprise you what a teen can do. But depending on how you drive, a gear change will make more of a difference in the seat of the pants feel.

 

[Coronet 500]

Agree with Cranky, 318's can perform well in the upper range so a gear is a good idea and still there when the 340 comes along. A couple things about rockers, your pushrods are ball so look for cupped adjusters, although I've heard some can crack on severe duty engines. If you go for ball adjusters on the rockers then you'll need to change pushrods to cups. Remember that stock 318 cams are .390-.400" at best and the heads don't leave much more between valve retainer and guide so check them. You should be good up to .450" but the last stock set I measured was very different across the head. If you need help on how to do it with them on the engine just ask and you'll get an answer here no problem.

 

[WileE]

Some good advice from these posters here. I'll give you an example of one car I had. Years ago, I took a stock 318 Satellite, added blackjack headers (small-tube, I think 1 5/8 ? ) with dual-exhaust/Thrush mufflers (love that sound ! )... intake with a Thermo-quad... curved the distributor... that's it... car ran like a champ ! Got better gas-mileage,too (needed that during the gas "shortage" )

 

[1968charger]

Thanks for everyones advice! Yeah gears are also in my mind I want to get some 3:55 w/ sure grip