I have access to a couple of 351w roller blocks (supposedly, out of E350 vans, late 80/early 90 models), supposedly running, etc. for $350 each. My question is...are these roller blocks worth a crap for building into 400-500HP blower motors, maybe stroked out to 393? I don't know if they are worth the hassle, or if I should look for an older block capable of handling more HP out of them... I am not looking for a pure drag motor...just some road-worthy motor with some periodic drag strip use...
Late model blocks will take a bunch of abuse before there's any problems. Upwards of 600-700 HP pretty easily with a soft tune. As far as roller goes, if it doesn't have F4TE on the side of the block, it's not a roller. '94 and later were roller capable.
I have a couple of "running" 351 blocks ready for use (abuse) for under $400...assuming I want to do the "abuse" on them... I have just been afraid to use them thinking they are too weak for my ways of thinking to "use" them...
:16suspect IMO a 400-500hp blower motor isnt really a street engine, well not unless you have VERY deep pockets. 351's can be very good motors I have a friend that has a 72 grabber with a 351W stroked out to a 408 and its really stout.
Why do you need a roller block? The only benefit is that they can use a hydraulic roller cam without needing the retainer kit. A solid roller can go into any engine, and many aftermarket hydraulic lifters are coming out in the same mold, so they do not need retainers. The case can also be made that the roller blocks are weaker than early blocks. How many 289 or early 302 blocks do you see split in half? I have only ever seen pics and posts of roller blocks split. Ford made the blocks increasingly thinner and lighter over the years because of EPA requirements. Thinner and lighter equal cheaper and weaker. They also saved money by using lesser iron with low nodularity (low nickel content).
a 400-500 horse blower motor isnt even pushing it on a stroked 351. should be a nice street motor (in my opinion) some of the new factory stuff thats supercharged puts out similar power with less displacement. I dont know about the deep pocket deal,.... I have holes in some of mine that or the wife is robbing me
Set of victor Jr's, 351w standard 4" bore (or 4.030, etc), 3.5" stroke, lower compression, Victor Jr intake and a CSU blow thru carb and a good matched turbo will make upwards of 1000 HP if it's tuned right and lots of boost. Best part is that it can be plenty streetable depending on how much you want to put up with. The 351w is EASILY built to make that kind of HP. There are 3 replacements for displacement. Nitrous, boost, and high RPM.
There is a difference between years. They can't use cheaper and thinner iron, and still have the same strength. Physics apply. Also, no way in heck would I use stock rod bolts in a 700 hp engine. I know the rods might handle it with plenty of work, but the rod bolts suck. Even after serious time (and/or money) put into the rods, I think I would just spend the dough on some stronger rods. They are cheap enough considering you will spend plenty (or sweat equity) on prepping stock rods. Even after all the work you would put into stock rods to handle that kind of power, they would be so marginal that I would be nervous every time the thing ran. Personally I would trust a stock early block to 700, stock crank to 600, and stock rods to 500. That's just me though. I am no engineer or anything, and when I say stock on all these items, they would still have max machine and balance work done. Just my gut feeling. I wouldn't trust a block made after about 73 to more than 5 or 6. Again... my gut feeling.
If the 351s are so capable of this kind of power, why do we screw around with the relatively "wimpy" 302? The 351 drops right in, so why go 347 and stretch the 302 block to it's 500+/- limit when we can drop a 351 in there and get much more power with less to worry about? I would MUCH rather put in a motor that is 400-450 HP, but safe up to 700, than a 400HP motor that is only safe to up around 500... Also, what is different about the 351 block that keeps it from splitting at some imagined high-point (500HP in the 302)? Isn't the 302 a Windsor motor, wouldn't they be built pretty much the same way?
Take a look at the blocks sitting side by side, sitting upside down (mains facing up) and empty (no crank, rods, pistons...only the block & main caps). The difference is huge. The mains on the 351w are MUCH beefier-especially the '69-'71 blocks. Main caps are 10 times thicker & stronger. The valley is thicker material the front main web is noticeably thicker, the deck is quite a bit taller and thus the cylinders don't protrude down into the crankcase quite as far as a 302. 351 had 3" mains and 1/2" bolts 302 has 2.25" mains (which is another debate in itself...kind of like the long rods vs. short rods debate) and 7/16" bolts, the rod journals are larger on the windsors vs the 2.125 302 rod journals. Head bolts on a 302 are 7/16 and 351w is 1/2". 351w decks are thicker. Everything about a 351w is stronger and built better than a 302. Matter of fact, the 351w block resembles a 460 in that they are quite strong and heavy..with the exception that you can punch out a 460 block .080-.100 and still have enough cylinder wall to be safe. Can't do that with a 351. And I'm sure someone is going to nit-pick about the larger main journals being too big...something about spinning main bearings because of surface speeds...well I can tell from experience that if it's set up right, it won't have any bearing problems. Don't think for a second that I take it easy on any of my stuff... About the only problems I've ever had out of a 351w are (1) a broken stock crank at about the 600 HP level (unbalanced assembly, 14.7:1 compression, agressive tune and 7700 RPM...went 2 full years like that) and (2) broke the mains out of the block. AGain, an aggressive tune, 2 full years on it at about 7000 max RPM. Also broke a SCAT 408 crank last year, took out the block but it wasn't the block's fault. The main webs are the weakest link, in my experience (if you have good rods that is) but they'll put up with a hell of a lot more punishment than a 302 block will. I'll state it again...with a GOOD tune, good balance job and some careful thought & planning, there is no reason they can't do 700 HP for quite some time. There's some turbo 351's out there going over 1000 and they seem to be doing well.
All of the above... PLUS! The 351w is soooooooo cheap to convert to 393! You can build a 393w for far less than a 347. Even if you figure only building for 1 hp per cube, you end up with almost 50 more hp right off the bat.
Oh, if I got a 351 block, I would DEFINITELY do a stroker kit, at least the 393... That is why I say 400 HP, that would be right at 1hp/cube and should be an easy and reliably running engine. Not stressing anything out, and no fears of running 6000-6500rpm and breaking something.
