Is a 351 worth it?

[Pesty351]

I'm running a 650 on mine without issues.

[Pirate]

A 650 won't be enough for a built 351.

It depends on the motor. I've seen 600-cfm 4-barrels work great on a couple of 460's, and I've seen one case where a 750-cfm Holley worked great on a mildly-modified 302.

It's weird, really, and also depends on what he's going to do with the heads and camshaft. If I had a choice for a fairly inexpensive carb, I'd pick the Barry Grant Road Demon 625 for the motor he's proposing to build.

[andymac0035]

they made a HO, which had 210hp, all the way back to 84 and according to the forum I was read it was the only 351w put in the trucks from 85 until they went to efi. It has a beefier cam, 4v heads(not sure which yet though or did they only make one type of 4v heads, the e7's are 4v right?) and then a different intake and a 4-barrel carb.

The (non-HD) F-250 had a 2-bbl and a 4-bbl option. The 351 HO was only available with an automatic unless you got an HD F-250 or an F-350. The 2-bbl version was avialable with a manual tranny on the standard duty F-250. Probably not too many around though.

[pvillese]

351 looking more likely

The (non-HD) F-250 had a 2-bbl and a 4-bbl option. The 351 HO was only available with an automatic unless you got an HD F-250 or an F-350. The 2-bbl version was avialable with a manual tranny on the standard duty F-250. Probably not too many around though.

So is this 351 HO a rare find? I think I'm going to pick it up. It was running when he pulled it but it has been sitting for a few years so I'm guessing I'll need to do a basic rebuild to freshen all the seals and clean up the cylinder walls which have probably gained some rust. The only thing not included is the carb and he is tossing in a c6 tranny. The price is right(more bartering of things I have and don't use).

I can't imagine I would want to put the c6 in my car but if it will fit I'll keep it around in case my AOD fails and I don't have the money to rebuild it or at least use the C6 while I rebuilt the AOD. I don't image a c6 is really worth much to sell right?

Does anyone know what ignition will be on the engine, is it the duraspark?

Just out of curiosity, my CFI could not support even a stock 351 right?

I was looking on (I think) Holley's site and they are going to be coming out with some 4-barrel cfi "carb replacements", depending on the price that could be an attractive option. Due to budget though I'm really leaning toward the 650 holley my brother has and that way I don't have as much invested when/if I do go to multi-port injection. Holley's site even suggests a 600cfm for a mildly modified 350(their charts are general and just rounding off the displacement).

[andymac0035]

The 2-bbl would be the rare find, the 5.8 HO's are out there (and more common), but many have been ridden very HARD. Based on what everyone is saying though, it won't be a roller block (I don't know how important that is).

IMHO, a C6 is always a good thing to pick up if it's cheap or free.

My 81' CV had a 351 2bbl out of an E-350. It was converted to fit my car (oil pan/waterpump/ect.) and switched to a 69' (points) distributor...along with an edelbrock performer (II?) intake with a holley 600 4-bbl carb. Other than that (and no emmisions) it was basically stock internally. It ran good, but the tranny was never right on that car......

[gadget73]

I would not seek out a 351 HO. Nothing that came with that is really worth keeping if you're planning to do a real motor. The heads are crap, the intake sucks, and the cam is also pretty weenie. All of that is likely going in the bin, so don't bother looking for special stuff to put in your scrap pile. The single coolest item about a 351 HO, and the only one I'd personally make an effort to re-use is the air cleaner that says 351 HO (or is it 5.8 HO?).

I would still make it a point to look for a later block. The roller hardware is a worthwhile thing to have, and I'd go so far as to say the stock 351 roller cam is a wee bit better than the 80s 351 HO cam. Still pathetic if you're planning a real build sure but at least you can sell it to someone. Its the same as the Explorer cam.

[Pesty351]

CID x RPM x V.E. / 3456 = CFM

[pvillese]

CID x RPM x V.E. / 3456 = CFM

So even if I expect 100% V.E., which I'm going to guess I wouldn't be able to get and the fact that I'm hoping my MSD box that maxes out at 6000 rpms is sufficient then the formula gives me in the neighborhood of 609 cfm, so the 650 should be fine, it wouldn't be an issue that it is larger than suggested would it?

Since this needs to be on a budget I doubt I can get a roller block, I don't think they are that common right? They didn't make them until 96. When I talked to my brother about the swap he suggested I buy a crate engine or at least a crate short block but there is no way I could afford that now. So maybe I can get acceptable power form this block I found for now and in a 3 or 4 years get a sweet crate engine. I'm thinking 250hp (possibly 300 hp depending what I have money for) would be a huge improvement over what I have now and the torque of the stock 351 should be more than enough to have fun and not have a problem with my small camper.

Does anyone know if the C6 will bolt right in? Is it the same length and connection as the AOD so I could use my stock driveshaft?

[Pesty351]

Well my 351 out of a 77 ltd has stock heads this cam .450 int lift, .474 exh lift 280 290 duration, Edelbrock performer intake and carb, with bbk exhuast. I was dyno'd at about 220 rwhp and 320 rwtq and I'm getting (when I'm nice to it) about 17 mpg. So 250 shouldn't be to hard of a goal to reach. Just keep it simple the simpler it is the more reliable it will be.

[gadget73]

There are two C6 transmissions. One uses the big block bolt pattern, the other has the smallblock pattern. You'd need the smallblock one. I wouldn't go C6 though. They're heavy and power hungry. If you really want to ditch the AOD for whatever reason, the C4 is a more efficient transmission. THe AOD can easily be built to handle that kind of power, and you'll get better economy out of it with the overdrive gear.

Roller blocks are found in 1994+ 351 powered vehicles. Wander around the junkyard, you just may find one. They're not as common as a flat tappet motor but if you can get one for a similar price, it would be worth it for durability reasons. I would not pay a huge premium for one, but I would pay a little more.

[pvillese]

Awesome to know decent gas mileage is still possible, I was a bit worried that it would be around 10mpg.

I'm only asking about the c6 really to see if it would be worth to keep around or if I should just try to sell it. I'd really rather not give up overdrive. So if I would need to buy a different length drive-shaft to use it then I probably would just try to sell it or barter for a backup AOD.

The price I'm getting this engine at is just too good to pass up. I doubt I could pick up another plain 351 for what I'm getting it for let alone a roller one. Not to mention that it should be an easy rebuild since it was running and may run now if a carb was just put back on it.

[Pesty351]

Awesome to know decent gas mileage is still possible, I was a bit worried that it would be around 10mpg.

That is with a 5-speed though an auto might munch on you a bit.

[pvillese]

That is with a 5-speed though an auto might munch on you a bit.

Forgot that you have a 5-speed. A 5-speed would be nice but I don't think I'll be doing that anytime soon. As for the drivetrain, does the 5-speed bolt right in or did you need a custom driveshaft made? I know there is a lot of work getting the peddles in and cutting the floor for the shifter. I know when we swapped my brother's mustang from an auto to a stick we needed a different length driveshaft.

[Pesty351]

No the drive shaft was fine the pedals were the only hard part. It really isn't all that hard though. It would probably be easier than a c6.

[gadget73]

5 speed would be more fun than a C6 too. I've only driven two C6 vehicles, both tired trucks, but they really did define "slushbox" for me. I imagine they don't all feel that way but tired pickups with gutless motors don't have very snappy transmissions.