I don't know enough about Ford Engines to say which way to go on valves, so listen to the other guys. One thing mentioned by a couple magazines in the past was that the Big block engine in a truck likes a free flowing exhaust, so if you haven't considered it yet, you should be thinking headers, freeflowing mufflers and pipes sized appropriately for you setup and what you want to do. If you do get new exhaust pipes, consider putting in a X pipe crossover or a H pipe(not as good according to Hot Rod Mag, but better than none). The X Pipe and the H pipe will improve your torque curve across the power band and it is relatively cheap to do.

BTW I mentioned "Appropriately" sized exhaust etc. Too big a pipe can be as bad as too small. Have a good shop talk over what you are doing and what you plan to use the truck for, so they can make suggestions. Pipe sizing can shift your power band to bad RPM ranges. As a broad guideline, really big pipes will require the engine to rev a lot higher to get power, smaller pipes will move torque down to lower RPMs. But there are exceptions so ask the shop, or this list.

Good Luck,

Jim Henderson

 

Jim, Im not a big fan of headers. Cost too much, rust out fast here in salty Michigan, and my experience on the current 351M, no difference in power. For exhaust I plan on iron manifolds (unless I HAVE to get headers to fit), and either 3" single or 2.5" duals with the crossover or X pipe (I read the same article in HRM). Thanks for your input!!

Nathan

 

i'll tell ya from my experience on that. ran stock exhaust manifolds for years on my 472 in my f-150 and the motor ran just fine it had lots of power. then i bought a set of L&L headers and this is no bull squat, the difference in power was like going from a 2bbl. to a 4bbl. that noticable. if you buy a great set of headers you'll get exactly what you buy a great set. they use a thick flange at the heads and they don't leak, mine i've never had a leak out of them since i put them on years ago. now to everyone i'm not bragging about them i'm sure there are lots of ya out there that have bought a good set of headers and were fine with them. but i put my cash down on one pair that was great and the rest is history. just wanted to let you know of my past and maybe you'll change your mind, big blocks love headers.

 

As for the vavle sizes I would say go with 2.19 intake and 1.72 exhaust. The 2.19 is pleny big for the intake and the 1.72 will help a ton on the exhaust side. As for cost, I know with my machinist if I have to have him put in a set of seats it really isn't much more to have larger valves installed. I mean, he's already setting up to cut out for the seat anyway, it's not hard to cut it out a little bigger. I would say that if you put in the larger valve and did a pretty good port job on the exhaust you could gain an honest 25-30 hp easy. As for hardened seats, the manufacturers only put hardened seats in after '74, when leaded fuel died. And even then they didn't "put in" seats, they just "flame hardened" the area of the exhaust seat. If your heads are older than '74 or if you are going to a larger valve you need to have hardened seats put it. Don't skimp here.

 

2v has 10.5 4v has 11.0 75.8 cc chambers

 

Just a piece of info., I have 71' heads, Kieth Black Hypereutectic flat top pistons, at about 10.7:1 compression and my motor runs great on 93 octane.

"Stuck with a m*par, Settle for a ch*vy, Happy with a Ford!!!!"

 

Thanks. Im going to probably use the KB hype-utes with 22cc dish for about 9.9 comp or so, hope it'll fly on regular fuel

Had a little dissappointment, loaded my freshly power washed and tapped C9 block in the truck to take to the machine shop and noticed two crackes in the back, behind the tranny mount face, in the water jackets Had to pull out another block. This one is a D1 block, looks good. Anyone know if the cracks in the other block can be welded up for future projects? If not I have a premo race block for someone, just needs the water jackets filled!

Nathan

 

KB hypereutectic pistons;
My machinist said that he has had several customers burn holes in the top of them. Not sure why, exactly, but he said the ring end gap seemed to be the critical point. He said you have to get that right or there is a good chance of melting one down. I went with forged.

 

Is 74 for sure the year when they went over to hardened seats? i was running leaded gas in my 73 429 for the first few weeks after i had freshened it up and put it in my truck (because i read a post saying they thought 73's MIGHT require leaded), but then i read a post on this site saying that they didnt think anything newer than 71 or 72 (dont remember) needed leaded, so i stopped using it. now i just read a post that for sure anything pre 74 needs leaded? any thoughts?

 

save money and use cast pistons there is nothing wrong with them. save the extra cash for other mods. don't be scared away because their cast they are very durable, mine are .060 and have well over 100,000 miles on them with no problems.. just my 2 cents trying to save you a buck or two..

 

79Supercab,
I think I posted that and it was based on what my machinist said. I asked him specifically, because I knew all the smog stuff went into effect in '72 so I was thinking that was the year that the manufacturers began the "flame hardening" of the exhaust seats, but he was sure it was '74. I trust him. He and my dad have been good friends for a long time so I feel he would tell me the truth. He'd have no reason to lie, anyway, and he really knows his engines, especially Fords.

 

Cast vs. forged
I know in my rebuild I spent over three grand so saving a couple of hundred on cast pistons was crazy. I know PAW has a few kits, depending on your application that you can get forged for $100 more. If your going to rebuild a 460 and put any of the small chamber heads on it, you can use stock-type pistons and you'll have around 9.5 to one. You can get a rebuild kit from PAW with forged pistons for that combo for like $345 total. Why try to save the $100. You can take the forged pistons out and re-use them. Who knows you might want to put nitrous on it after a while!!!!!

 

The reason I went with Hypereutectic is because the are stronger than cast, but cheaper than forged. I had/have no intention of putting nitrous on my motor in its current form. I did hear about the burning of pistons, but from what I was told it only occured when to much timing was used. When I asked what the considered 'to much timing', I was told in neighborhood of 42 - 45 degrees of total advance. Since I have no intention of that either, hypereutectic was an obvious smart choice for me.

TBirdGuy

"Stuck with a m*par, Settle for a ch*vy, Happy with a Ford!!!!"