I have a 68 Coupe that I am wanting to drop a 351W into, eventually with an EFI set-up. I am looking for 300-400hp reliable Sunday driver. My question is what is the exact difference between a 351W roller and non roller? I have read that they can provide different power curves but have never seen anyone post what the different curves would look like. Is that the only difference power curves? Is the block what makes it a roller or non roller or is it its internals? I have researched and found that the older 351s 69-74 were built "stronger" than the more recent blocks. Can anyone validate that? With that being said is a roller block that is weaker (95-97) or a non-roller that is stronger (69-74) better for what i want? I would also like to put a turbo or a supercharger on it once its GTG, will that change my choice in block? I know you guys know more than me so im coming to you for help, be gentle, thanks

 

Welcome to the site. You are correct between your distinguishment between the blocks. 94+ 351w's are commonly found to be roller-ready blocks. These blocks can be distinguished by the casting number F4TE. Older blocks, 69-74 are often said to be stronger due to the higher iron content. Having said that, if you stick to the numbers you are refering to (300-400), either block will be fine. It is only when you are making extreme power that those factors come into play. It can be very difficult to find an F4TE block. The roller motor is ideal because there is less friction, which means more efficiency, which results in more power. I'm sure you'll get all sorts of answers on this, either block pushed to the limit will make some serious power.

 

Roller cams make more sense now that motor oils with enough zinc and phosphorous are harder to find. I've thought about converting mine with a kit, but for power reasons mostly.

 

IMO the 300 to 400 HP goal can be met easy with a set of aftermarket heads and a fairly mild cam, making the real need for a roller more dependent on the state of today's oil than the potential to make reasonable power.

I have learned from trial and error that a big cam is not really as important of a factor for making good power when an engine has good aftermarket heads (over stock heads where cam selection is more important imo).

 

Pretty much was said above. Consider though that on a 351 block, whether it's an older non roller or a newer roller block, if you're at the point on either where you're worried about block breakage, you're looking into aftermarket blocks and are producing over 600hp.

300-400hp range can easily be met in something that has really good manners out of a roller 302, which is a somewhat easy block to find.

On the matter of cams, it's a good idea these days to always go roller just because of modern oils like was mentioned. Flat tappet cams can be a pia to keep alive during break in these days, and it requires spring changes to use special break in springs.

Also a roller cam, by virtue of the lifter having an actual roller, has essentially 0 friction and as a result can run more aggressive lobe profiles. The valve opens sooner and faster to closer to max lift, stays open longer and closes faster. The result is that on a roller cam with the same "numbers" in terms of lift and duration at .050 as a flat tappet cam, the roller cam has a power range around 500-1,000rpm wider, and makes more total power in that range. Roller cams will always outperform flat tappet cams, but they cost more in terms of the cam AND valvetrain, since they need better springs to maintain stability(more inertia to control).

Fwiw the 302 in my 67 is pushing close to 400 at the crank now with heads, intake, exhaust yadda yadda. The only thing stock is the block basically, with a custom hydraulic roller from Ed Curtis at FTI. It has a very stable idle, runs great with wonderful street manners, pulls off a stop really easily has solid low end power, and an absolutely massive torque curve from 3,000-6,500rpm. Runs great down low and pulls hard all the way to the light at 6,500rpm.

 

Any block would work just fine for a mild 300-400hp build..The only advantage to the newer roller blocks is that they accept the factory roller cams and lifters which are cheaper than aftermarket stuff...So basically it might save you a couple hundred bucks on the lifters...If you are thinking of supercharging down the road I would think about an early block or aftermarket..

 

Frankly, If I was considering supercharging I would be looking hard at a DART block......

Of course if you are SERIOUS about supercharging, you need to build a whole different engine, so what ever block you use for a NA build is pretty much moot.

A retrofit cam kit (spider and bones with a reduced base circle cam) can be put in ANY 351 block, this is what Jim used in his 66 with a 69 351 block. It works more than ok...

 

If engine noise bothers you, be aware that some built roller and flat tappet engines can produce more ticking noise than OEM.

 

The actual strength difference between an early and late block is minimal.

 

First off thank you very much for thoroughly explaining the differences to me. Ive been reading other threads and was at the point of confusion. So the over whelming result is that for the 300-400 hp range either block would be good. Would that also be true for the 400-500hp range? And does it matter which block for an EFI conversion?

After reading your post and really looking at the blocks other quality superchaged or turboed cars are using, I think im gonna just focus on building a little higher quality(& horse powered) block to start for the get go. With a 400-500 hp number in mind instead of building it up to say 375, than either buying another block or doing the internals to support a supercharger or turbo. I think this idea would be cheaper in the long run too.

So to sum it up i can get a 94+ block, from say an econo van or f-150 and have an already gtg roller block. Or if i happen to find a stronger 69-74 block i can add a Roller Retro-Fit Kit, like the one from comp cams(not name dropping, but the only one i found online) and some special lifters for around $250 and have a gtg roller block. Correct me if im wrong but i could have the best of both worlds.

69mach1377-Let me know if you decide to go the route of a conversion kit, i would like to hear/read your experience.

JMD- whats the thread name of "Jim", id like to ask him how his project went.

Once again thanks for all the help. If i missed anything please let me know