77 318 economy/performance mods

[shadango]

I think Chryco means "without headers, exhaust and maybe a cam".......or maybe not?

My 318 has a 4bbl, manifold, cam and headers along with x heads....yes, its low compression, but it sure feels like it runs to me when it winds up!  I have driven some plain old 2 bbl 318s before and there is a difference.

But I agree...just slapping a bigger carb and intake on a stock 318 without given it bigger lungs and such (exhaust) probably wont do a lot.....incoreasing air/fuel going in, you have to increase the exhaust capacity too.

[HP2]

Okay, so we're limiting this to bolt ons. Is a head swap a viable bolt on to you? Like CP mentioned, the later model swirl port heads will help out. If you really want step it up, a swap to magnum heads is even better because of the smaller chambers, but requires different rocker arms, lifters, push rods, and intake. Shim type head gaskets will also help with compression over the composite style.

[Chryco Psycho]

Yeah I was meaning if you just add the 4 bbl & intake I have not seen much gain , with better heads & cam & headers  the 4bbl definatly helps

[black71]

hey guys thanks for the help...as for as bolt ons anything is viable, just trying to do things on a budget

[Super Blue 72]

I guess it depends what you start out with and your definition of gains with a 4 barrel/intake alone.

Way back when I had a wheezer '81 5th Ave with a 318 lean burn 2 barrel carb and switched over to a 600cfm Holley and Weiand 2p intake, big difference on the top end IMO.  With the 2 barrel factory set up, going up to Montreal in Vermont I literally had the pedal on the floor and a VW Rabbit zoomed by me.  Don't know how fast I was going asthe speedo only went up to 85mph, wild guess was 90 something mph.  After the change to the 4 barrel setup I was tagging along a late 80's Trans Am on the highway and he said we were going about 105mph and I still had some pedal travel to go before the floor. 

Bottom end would bog if you hit it too hard as there was not a cam change but I did open up the exhaust a little.  I switched to a Rochester Quadrajet (had it lying around and wanted the smaller primaries) and the bottom end was helped out a little.

It didn't make it a legitimate street racer, but definately more fun to drive. 

[black71]

what year/rigs did the 302's come in

[72bluNblu]

what year/rigs did the 302's come in

'85-90 for the 302's. Mostly trucks I think? Dakota's etc.

You could just change the head gaskets and pick up some compression. Not sure what the stock thickness is, but I bet its at least .039", if not more. Going to a SCE head gasket with a .021" thickness (from .039) would grab you a ~.4 bump (ie, 8:1 to 8.4:1, or if you're lucky and its actually 8.5:1 already up to 8.9:1)

11 MPG with your 318?  Yikes Shadango! I have a 625 cfm Carter, an Eddy Streetmaster intake, 1 3/4" headers (for my 340!), stock 1972 318 heads and 2.76 rear gears at the moment and I still manage 14 mpg around town, and 17 mpg freeway. And I KNOW I'm running rich and lead-footing it!

[shadango]

11 MPG with your 318?  Yikes Shadango! I have a 625 cfm Carter, an Eddy Streetmaster intake, 1 3/4" headers (for my 340!), stock 1972 318 heads and 2.76 rear gears at the moment and I still manage 14 mpg around town, and 17 mpg freeway. And I KNOW I'm running rich and lead-footing it!

Yeah, I know.....I am running a bit rich too....

I wouldnt mind tweaking  little more mileage from her....but I wont complian the SMILEs per gallon is still higher than any other car I have driven...LOL   

(I know, bad pun......but hey its early and its monday)