Sm_Block to Bg_Block X_Change

dmfconsult · #1 (**permalink**) 08-13-2001, 05:14 AM

I was thinking about building an engine as a winter project. I was wondering what all would be involved to go from a 302 CID to a 460 CID. Would I still be able to use my Tremec 5 spd trans? Need a new prop shaft? Mounting locations the same (engine and trans)? Does CRL sell a big-block specific kit?
Also, why is it when I see 351 CID's in Cobras they are all Windsors and not Clevelands? Is there a significant difference??

Thanks,
DFord

dscott · #2 (**permalink**) 08-13-2001, 08:37 AM

The first thing to check is the frame to make sure a big block will fit. Classic has a small and a big block frame. The small block frame has a metal floor pan on the drivers side footwell. The big block frame has a fiberglass foot box. The change can be done without to much trouble. You will need to change the front springs, Radiator and fan depending on the hp of the engine and which combo you have now. Headers, frame mounts, motor mounts, trans mount, driveshaft length. The trans will work if you install a scattershield. The steering shaft may also need to be alterered for header clearance. The wiring is the same, shifter location may be slightly different. It sounds like more work than it is. Let me know if you proceed I can help with part #'s etc.
Don

dmfconsult · #3 (**permalink**) 08-13-2001, 08:47 AM

Thanks Don, can you speculate on the popularity of the Windsor in the Cobras? I'm getting a lot of "car dude opinion" that the Cleveland is better..
Dave

CobraEd · #4 (**permalink**) 08-13-2001, 09:56 AM

It seems to me that the big claim to fame on the Cleveland was the better breathing heads. I don't think the block was any stronger, in fact I think I remember reading that the Cleveland block is weaker than the Windsor (I could be wrong on this)

However with all the terrific aftermarket heads on the market now for the Windsor, there is no longer any performance advantage with the Cleveland. Besides it is a heavier engine.

Ed

dmfconsult · #5 (**permalink**) 08-13-2001, 10:28 AM

I was just told that the Cleveland has 4 bolt mains, I did not get an answer when I replied with the question "does this mean the Windor has 2 bolt mains?"
Dave

Brose · #6 (**permalink**) 08-13-2001, 10:30 AM

I had similiar questions regarding Windsor vs. Cleveland. Check this link for a side by side comparison. Based on what I've read CobraEd is right on the mark.

http://www.sscconline.com/cleveland.htm

FYI - I have a Windsor on order from Don Scott -- I'm sure he'd build whatever you want, Windsor, Cleveland or otherwise (if you don't want to do it yourself). Good luck!

jwinkler · #7 (**permalink**) 08-13-2001, 10:33 AM

FWIW, I've got experience with two 351C-to-351W conversions (two Pantera buddies), and both happened because the Clevelands suffered catastrophic engine failures. The first ate its #7 rod bearing (and digested it through all the oil passages), and the second dropped a valve - that was some impressive damage! The bearing problem was attributed to a (well known?) Cleveland oiling problem, although what specifically about the oiling system causes it, I don't know. The valve problem is also apparently well known with stock valves - I think the stems are hollow and prone to breaking.

Also, it's recommended that the 351C blocks not be overbored beyond .040, so finding a usable old one may be difficult, whereas the Windsors are supposed to be fine at least to .060. The Cleveland heads are pretty impressive, at least in port and valve size, but given the number and variety of available aftermarket Windsor heads, that isn't a compelling argument for the Cleveland anymore.

IMOSHO :-), the only benefit to going Cleveland instead of Windsor would be for style points. With the aftermarket support for the Windsor engine family, I'm guessing it's easier and cheaper to get more reliable horsepower from the Windsor.

JLW

dscott · #8 (**permalink**) 08-13-2001, 01:18 PM

I agree with everyone (how's that for being easy!). The windsor is a 2 bolt block but I think a very good upgrade to the cleveland. The cleveland did have huge heads and did breath excellent but to get the horsepower you had to get pretty wild which in my opinion made it a poor street motor. I think with the aftermarket parts available for the windsor it is a much better choice.
Don

Double Venom · #9 (**permalink**) 08-23-2001, 09:02 PM

Playing serious catch up here! This one is easy.

Clevelands are for the oval guys! Especially the 4bbl head ones.

The torque is way in the upper rpm range, does little or nothing at the lower end, where most of us show off and can easily get beaten in the 1/4 by a simple built 302.

Don is to damned modest! Fellas, this guy builds one heck of a motor. What he tells you, you can take to church with you.

Don, if you don't post a picture of one of your done 351's I'm going too!

How about one on the dyno?
DV