331 rwhp

Toby · #1 (**permalink**) 03-30-2005, 01:18 PM

Keith,

I,m wondering if a solid roller cam 331 can be built to withstand 7000 rpm and make about 400rwhp and still be streetable. My current 347 makes about 300rwhp in my cobra. We have spoken on the phone about my engine before and with all the problems I had with the build and re-build, I,m not sold on the reliability factor. I want another 100 rwhp and, I've heard that the 331 is an inherently more reliable motor, and the solid roller cam should help the engine live at the top end, huh? Please give me your opinion on this and thanks again for all your help. Plus I could use my .030 block and heads if you ported them and all.

Toby

marcocsx3121 · #2 (**permalink**) 03-30-2005, 01:55 PM

A passing comment from a pilgrim that admits to having zero experience with small block Ford strokers: reliability of a given engine is far more dependant on the quality of the machining, assembly, and components than the particular displacement. I have to seriously question why a 331 would be more reliable than a 347, other factors being equal.

There's a local Mustang drag racer who has made over 1200 RWHP with a turbo 347 without "reliability" issues.

ruslow · #3 (**permalink**) 03-30-2005, 02:48 PM

I think the big reason is the rod ratio.It is more favorable on the 331.Since the oil rings are above the pin.But who am I to know.Stan

Toby · #4 (**permalink**) 03-30-2005, 03:17 PM

Marco,

I really tried to let your post go, but I just could not do it!

First of all, this is Keith Craft,s forum.
Second, I specifically adressed the thread to Keith.
Third, the reliability issues that I have are a result of problems with the engine builder and not a 347 or 331 stroker, as I alluded to in the first thread this is a topic that Keith and I have spoken on before.
Fourth, you indicate in the first part of your post that you know nothing of ford strokers anyway.

Kindly butt out,

Toby

blykins · #5 (**permalink**) 03-30-2005, 03:25 PM

Toby,

I don't care if you tell me to butt out or not....but it's my opinion that you should be nice to the people who are answering your posts. We have a lot of helpful people on this site...any one at any time could have the answers or insight to your question.

I have a lot of respect for Keith Craft...but do you think he's the only one that knows what he's talking about? Marco was just adding some food for thought.

I'm sure Keith is a lot nicer than me....but if I were him, I'd wouldn't help someone who is so crass and rude.

jmarsey · #6 (**permalink**) 03-30-2005, 04:30 PM

Quote:

Originally posted by ruslow

I think the big reason is the rod ratio.It is more favorable on the 331.Since the oil rings are above the pin.But who am I to know.Stan

Stan,

In your example, rod angle is the concern, not rod ratio.

John

blykins · #7 (**permalink**) 03-30-2005, 04:34 PM

While taking a risk of being flogged for expressing my opinion....

The longer stroked combo would have a piston with a shorter compression height. Along with this comes oil rings that are in the wrist pin hole....steep rod angles as mentioned above, increased piston travel, and the possibility of the piston not being square or solid at the bottom of the stroke...

So in theory, the shorter stroke engine would possibly be apt to last a little longer....

Keithc8 · #8 (**permalink**) 03-30-2005, 09:38 PM

Toby we did an engine similiar to this for a guy in New York. What we did was a 3.250 stroke but we had a big bore block that made a 4.125 stroke and this got us 347 C.I. a different way. We did this engine with about 11 to 1 compression and with the Victor heads with shaft rockers. This engine made a little over 600 HP but at like 7500rpms. He had it in a Cobra and he liked it but it was about a 14,000.00 engine. This is what it will take to make about 475 at rear wheels. To make 400 at rear wheels we would need about 525 and this could be done with a 331 with about 11 to 1 compression, solid roller, AFR 205 heads, Victor JR intake and a nice carburetor. This combination should also get you about 400 to the rear tires. A complete engine like this could be done for somewhere around 9000.00.
The biggest problem with the 347 combination is not that the pin gets in to oil ring or the rod angles all though it is not as good as a 331, the biggest problem is the short cylinder on the 302 block. If the cylinder was longer at the bottem the piston would not come out of the cylinder at bottem dead center as much. When at bottem dead center the piston rocks quite a bit due to little support till it get back up in the cylinder some, this causes some wear on the piston, cylinder and rings. For longivity we like the 331 better, for racing applications you have the engine down a lot more and this is not as big a problem. I would rather run the 347 with a 5.500 rod to get the piston higher in the cylinder at bottem dead center but this would be a custom piston. Hope this helps a little. Thanks, Keith

marcocsx3121 · #9 (**permalink**) 03-31-2005, 04:48 AM

Your thread showed up on the home page list of recent posts, and I didn't pick up on the fact that it was "Keith's forum". If this merits an apology, I apologize. As far as "butting out", if you get this easily offended by thoughts from other members of this board, private messaging might be a better fit with your personality disorders.

Toby · #10 (**permalink**) 03-31-2005, 09:09 AM

Keith,

Thanks for the info, It appears that I will have to abandon this block to do what your talking about. I really appreciate your time helping me with a problem that was not yours to start with, and I will be saving my pennies to have you build this engine at a later date. Once again thanks!

Toby

uncltodd · #11 (**permalink**) 03-31-2005, 03:50 PM

Toby, just to kinda give you a baseline...

KeithCraft Motorsports in Plano, Texas built my engine last summer.

BDR #139, jokingly known as "Gunrack."

351W, 300+ HP rear wheels. They did my whole drivetrain, in fact, Tremec TKO 500 (and speedo cable that came unglued at twice the legal speed limit.)

Hey, 315 at the rear wheels is... impressive out of a carburetted 351 that starts after 2 primer jabs, hot or cold, and loves 91 octane gasoline.

Reliabilty? Don't have a clew yet, 1200 miles.

This is MORE CAR than I have ever driven in my life, thank you.

Look-my eyes are shot, I found out.

I'm a "streeter," not a "tracker."

Find your own path.

And please don't badmouth people on this forum.

UT

uncltodd · #12 (**permalink**) 04-02-2005, 04:36 PM

I think Toby and I are good now, I pray.

Gunrack should hit the street... again... in about ... end of next week.

Forgive me if I whine and moan. 16 weeks.

UT



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