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ford 300 6 mileage/little extra power build

16K views 15 replies 8 participants last post by  lt465 
#1 ·
I got a 85 f150 2wd with a 300 straight six that needs a clutch the other day and i figure when i fix the clutch i will pull the motor and do some things to it to mainly get better mileage and also have a little extra power to keep up with stock pre-1996 350 chebbies rated at around 200 horse, dont need to beat em just dont want to be made a fool of by them.

I,m figurin on getting some efi manifolds, do a little port work, maybe an aftermarket 4 bbl intake and carb or 2 bbl adapter and carb, a mild cam, get rid all the smog crap, a free flowing fairly quiet exhaust system, and a real good tune up, the truck only has 70k on it so im hoping things are pretty solid yet im gonna do some inspecting tonight, compression check etc.. im just looking for suggestions.

i would ask on the performance six website but it doesnt seem to be working.
thanks, rob
 
#3 ·
We have a customer who did something similar to a 292 Chevy that he has in a little 2 1/2 ton dump truck. The engine was getting very tired so he built another one totally stock except for a 4 barrel intake and a header. He bought a little Holley 4 barrel I think it was a 390cfm with vacuum secondaries. The only work I did to the carburetor once he got it running was open up the idle feed restrictions about .001 to cure a very slight rough spot in the transition. It runs absolutely great and gets much better mileage than before.

If you wish to change the cam I would probably use something from Reed that has a Torque Master lobe. Something very short yet more aggressive than stock to help the breathing yet still allow it to make cylinder pressure even with a low static compression ratio.

The 300 6 can be very bad about wanting to ping sometimes constantly while going down the road. Often times the distributor timing is wacky so that's another area where you could make some gains.

I think Offy used to say somewhere in one of their adds that their 4 barrel intake and a header was worth about 75 horsepower on a stock 300 6 which is a TON!
 
#4 ·
my g-pa and i are build a 300 race motor , not sure what it will go in, i am looking for a 60-63 falcon, i already bought the pistons, 12-1 dome top arias, got a alum Clifford 4 barrel intake, we built one for a friend, for his 60 falocn, it has ignition problems , motor has never over 5000 rpm and still has ran a best of 12.20, cam is good till 6500 mine will be a low 11 sec car ...check out fordsix.com
 
#7 ·
The stock Holley off of the 460 would probably work well on a build like this and it's certainly worth a try since you already own it anyway.

My customer with the Chevy had to wait a while before he got his intake manifold. They were a little hard to come by and they were back ordered. It was worth the wait.

I can't imagine the 300 Ford would react any differently to a header and a good intake manifold, it'll run excellent and I think that while poor the cylinder head is probably better than the Chevy design because it doesn't have the siamese intake ports.

In the past some drag racers used to take two Boss 302/351 heads and saw off one cylinder to make a head for the 300 which has the same bore and bolt spacing as the small block engine and a 4X4 configuration which makes it THINK that it's a 400 cubic inch big block. We all know how well those heads work on a 400 cubic inch engine and with some different pistons, custom intake and header they really worked. This is beyond the scope of the type of build you want to do however.
 
#8 ·
Heres what I did to my 300-6 in my 79 F150 4wd and Im quite pleased for what it is and I get 14mpg.


300 .060 stock crank and rods with hyper pistons decked .020

Stock 300 head decked .020 with stock valves and springs. I used Chebby 292 rocker arms for a little more ratio.

Crane 268H cam with a steel gear

Duraspark dizzy and box

Clifford 4bbl intake and Holley 390cfm cam

EFI manifolds and Walker downtube.

Probably makes around 200hp and 300ft lbs




For even more power you can use a 240 head with 305 chebby valves. More info at www.fordsix.com
 
#10 ·
I have owned 300's and if you can still get the Crane Cam get it, the Offenhouser single plane (for more hp) or the dual plane if you want tons of low end torque. Go to a junk yard and find an 89 up that will have the split manifolds, but headers won't yield you more hp unless you are going extreme. Something else I have found is the engines (the above build) like a 2.75" exhaust ran to about the rearend and 2.25 the rest of the way out.

I had EFI and find the Offy Dp and a 450 Holley made better torque.

No 302 is going to outpull the 300!
 
#11 ·
Thanks for all the input i really appreciate it, does anyone know the porting specifics on these heads, what material you have to remove for flow gains? Im planning on just doing some porting myself, i bought a subscription to that reincarnation automotive website and ported the d3's on my 460 and they turned out pretty nice, runs real strong, i just need to know what areas need addressing on the 300 6 head, all iv found so far is most of them have the thermoactor bumps that need to be removed but i dont know if they are supposed to be turned into a directional vane like the 460 heads or not?
Yea i heard a little bit about people cutting up boss heads and fitting them onto a 300 6 too thats pretty neat, gotta take a serious mechanic/machinist and some $$ to do that tho lol
thanks again, rob
 
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