Hi i'm new to the board and have lots of questions concerning my 78 f150 with the 4.9l I6.

Anyway i was think of replacing the cam with a Comp 252H. Can i use the stock springs with this swap. How easy is it, is there anything else that needs replacing.

I am also thinking of putting on some Hedman HED-89300 headers.

What kind of performance increases do you think i will see.

Later i will add a different carb, maybe a 2bbl or maybe a holley 600cfm.

 

from what i've picked up from talking to some of the other guys that have put 4bbl carbs on their inline six's, a holley 390 is more than enough carb for the 300-6 cyl...i don't know about the headers....as for the cam, i've been told that Crane cams are a good way to go, and use a 260 degree cam...

MontanaFord

 

I put in a 268 in my 300 and i use the stock spring and it works fine so i don't see any problem with what u want to do. If u put headers and a good intake and a small four barrel carb it will really wake up the engine. I put a offy c series intake and a 500cfm edelbrock on my and it works good. The headers took a bit of manuvering to get into place but nothing a little patience can't handle. One thing i suggest is to put in a new starter and a heat sheild for it because the heat from the headers will eventually cook the starter. It requirers unbolting your headers and alot of messing around to get it out(trust me). I figure my 300 should be sitting around 250-300hp right know and i hope to dyno it soon to prove it. You won't even be able to tell there is a 300-6 under my hood.

 

300inline6:
I planned to do the exact same setup as you, except I was gonna have the head done to. Question is was it worth it? Could you have spent the money upgrading a 351W and got more horsepower for your buck? I'm debating which path to take, buy a old 351W and rebuild and build that up or stick a bunch of money into my 225K six.

 

You could rebuild a 351w. They are great engines and there are many parts out there to build them for what ever you want it to do. I did up a 300 6 because I had one kicking around and really wanted to see what one could do. There were people who told me I was crazy to do up a 6 banger and it made me want to do it even more. There was also alot of people I talked to that were very intersted in it because everyone had heard that you could get alot of power out of these engines but no one had evey seen one done up. If you decide to do up a 300 6 I don't think you will be disappointed (I sure wasn't) but in the end it's your choice. I just like being different and taking the road less traveled.

 

i'm going to be building my spare 300 that i bought...here's my plans...

deck the block, bore .10 over, mild port and polish on the head, offy 4bbl intake w/ 390 holley (most likely), MSD ignition system, efi exhaust manifolds, true dual exhaust (what kind of exhaust, i'm not sure yet...either a pair of 24" glasspacks, or flowmaster 40 series...turned down to the pavement just ahead of the rear axle...behind that, i plan to eventually (when i find one) put a zf 5 speed tranny, and probably move to 3:73 gearing in front and rear axles....

MontanaFord

1984 F-150 4x4 300-6 4 spd 3:55 gears 297,000 miles (all original to my knowlege)

P.S. Why do all this to a 300? Why not? It'll give me something to spend my extra money on, and give me something with which to keep my time and energy occupied.

 

300inline6:
Which headers did you choose and what is your truck: year, tranny, 4x4-2wd, everywhere I look they don't make headers for a 4x4, but people say some work. I'd like to use the hedmans or the dynamax's and will I still be able to get my starter out w/ headers on, b/c I have these cheap lifetime warrenty advance auto parts starters that give me about at the most 6 months.

 

I choose the hedman headers because they were the easiest to get where I live. I have a '78 2wd that originally had a screwed 351m in it with an auto tranny that i took out and put in my 300 6 with a np435 tranny. The hedman headers work with both the 2wd's and the 4x4's (personally installed them on both). The headers are dual outlet so the first three collect into one and the back three collect into one. One set of pipes run beside the starter and the other set run under it. To get your starter out you have to unbolt your headers from your exhaust and your engine and use a prybar to push the headers to one side and work the starter out. It might be possible to do it without unbolting the headers from the engine but it was a while since I did it so I can't remember if you can or not. The hardest part is getting mounting bolts for the starter in and out because there is little room with the headers there. It a little tricky but become easier once your done it a couple of times. I would still recommend that you get a heat shield for your starter because the headers come pretty close to it and give off alot of heat and can wreck a starter pretty quick.

 

The mods I did to mine are:Offy 4 bbl intake,600 Holley, ported head with 1.92 intake and 1.6 valves, Erson cam(I will have to find the specs), bored .040 over, Hooker super comp 3 into 1 x 2 headers Mallory unilite dist. Mallory promaster coil and mallory hyfire 4 ignition box. We figured hp in the 300 to 330 range. It surprized more than a few people when I popped the hood. Nobody expected to see a I6 under the hood.