335 folks, Do you think I will be happy with a 351M with RV cam, 4bl carb and dual exhaust. This truck will pull a 16' trailer with small tractor and 5' mower. I think stock it only had 110-140hp, Roughly how much horsepower will this combo produce. Zero degree gear and chain and all emissions removed. Thanks/Robert

 

It will be better than stock, but it will still be pretty weak. Low compression and a down the hole piston are not your friends when it comes to making power.

I take it you are going to leave the rest of it alone. How many miles on it? Adding performance to a worn engine soon results in a broken engine in many cases.

If you have read much in this forum, you know the formula for power is to put the 400 crank back in that motor with some 9.3-ish compression, then the cam, headers, intake.

Since what you are doing will also work with the 400, try it. If you are happy with the results, drive with pride. If not, your new goodies can still be used with the 400 crank/piston etc.

I would guess 180-200 hp max out of your set up. Be sure to include valve springs and a proper valve train work up with the cam. Stock 351ms never saw much over 3500 rpm, so you don't want floating valves at 4500.

 

Dear 85,
Thanks, I thought I might try to get this truck running, and if I really like messing around with this old stuff, I could build a good 400 later, as you have suggested. Thanks/Robert

 

Also like I suggested on some other posts, but it's pretty well out there, if you can stump up for a set of 302 CC aussie heads, that would be a good thing. And again it will all be good if and when you upgrade to a 400.

 

The root of the majority of 351M performance deaths come from dropping valves(they have triple groove stock) and they dont like to rev much past 5400 rpm. Modify one that will rev past 6K much and you'll have to blueprint the oiling route (not so much modify but attention to assembly detail).

Sounds like you won't push your motor that fast since you intend to do alot of hauling. I would suggest a dual pattern cam that favors the exhaust, and search out the tighter lobe seperation angle (LSA) when looking(108 to 112 will be fine for you, just a flatter torque curve with the wider angle). Have one in mind? Stock valve springs only clear about 0.480" lift before you have to worry about spring bind. However there are options like a cam kit that will include matching springs, or swapping in a suitable set that has enough seat load, and lift clearance for the cam you choose.

351 cubes will work with 1 5/8" primary header tube, and 1.75" will help mid range be fine with 4.10 and lower gears.

Your thoughts on what carburetor you will run?

Before you begin your tear down, I would suggest doing a compression test of the cylinder to know how your rings are doing. Hopefully you have at least 125psi of cylinder pressure - otherwise a cam swap may not yield any significant increase in power. HTH

ps here is one impressive build(keep in mind the compression ratio for the final build) Installing A 400M Short-Block Into A 351 Cleveland Stroker Engine - Muscle Mustangs & Fast Fords Magazine

 

The pro-comp heads in the article scare me as they do not have a good rep here in aussie. I believe that they went offshore (China?) at some stage and quality suffered. They well have been ok when the article was written. The numbers do indeed seem very impressive. Can anyone comment on their validity from similiar builds as this maybe shoud be a sticky in the top section of the forum? what do you think CTUBUTIS?

 

Dear Brutal,
I want a 600 holley, a lot of people say go edrebrock, they say there is not much to adjust, but the holley is so damn pretty.
Will I be sorry with the holley? Thanks/Robert

 

While the AFB is a simpler design, it is also simpler to service. I've always been a fan of less moving parts for reliability, however I know from experience that a 750 holley VS all around outperforms a 750 AFB VS - albeit a more intimate relationship and respect for handling exposed fuel - some people just are not cut out to handle that risk.

http://www.holleytv.com/video/232

 

great read and spoke with scott mpghead on this build. mine has little more compression and better flowing heads/intake with air gap and my heads flow really close to the procomp heads. not running the big cams like they are, little more conservative for my application, .520 lift hyd roller.

 

Don't get the holley I have one on my 351m, and it runs like **** compared to when we put my buddies Elderbrock on. You gotta re-adjust them hollies almost every week... just my two cents...

 

what carb was on your truck? why did you have to adjust so much. sounds like your butterflys are open to far at idle. what jets in primarys? several questions before calling it junk. Also the holleys will outflow a edelbrock in same cfm requirements like 600cfm holley compared to 600 edlebrock. edelbrock is a decent carb but several consideration need to be figured out before you put the boots to it. A holley is actually easier to tune than a edelbrock in my experience. just jets and powervalve in a vacume secondary. can play with the spring on vacume secondary on how quick to open.

 

600 vacume secondary or doublepumper? I prefer the holley due to tunability.