351 Cleveland heads to a 351 Windsor block

More updated info - Was sent an email referring to Price Motorsport in Indiana who manufactures various intake adapters and other parts for those interested in doing this swap.

Follow me along and I'll give you all the details. Most of the pics here were scanned in from other places, I don't personally know where, but they have been useful to me anyway. Take a look!

Well. Why would u want to do this? 351 Clevelands are great. What makes them great? Their heads. When Ford designed the first cleveland heads (aka Boss 302) back in '68-'69, they took a look at everything else out there and squished all the best ideas from everything into one neat package. Huge ports, big canted valves.. The first appearance of these was on a machine known as the Boss 302. This was basically a hipo 302 block with 351c heads on it. The 351c itself, however, did not appear until 1970. Unfortunately, the 351c block does have its shortcomings. A poorly designed oiling system combined with the thinwall casting leave some to be desired for heavy duty use. Not to say that the Cleveland's block is going to bring the average person problems (I have personally had a Cleveland with over 300,000 miles on it in perfectly good running order), but if you are building a real performance machine, this is the alternative. As for 351 Windsors - Their heads are nothing special really, simply a slightly larger version of your generic 289/302 heads. Smaller ports and valves don't flow anywhere near the way Clevelands do. The blocks, however, are well-designed, have a decent oiling system and are far less prone to failure. Not only are they stronger, but they are cheap and easy to find. Here's some specs to compare the two blocks:

There's a few basic areas that need to be modified to accomplish this swap.. I'll go thru each one:

Intake manifold:

You'll be needing a special intake manifold. Obviously, for those of you building a 302-based motor, you could use a Boss 302 intake. Of course as time passes, these get harder to find and more expensive when you do. For many years there was a company called Bush Performance who was casting new intakes, both dual and single plane versions. They eventually became B&A Ford and continued production, however they are now gone as well. Their intakes are still out there to be found, but like the Boss intakes, are few and far between. Luckily, in late 2007 Edelbrock stepped up to the plate and is now casting brand new intakes in their Performer RPM/Air Gap series, calling them the "E-Boss 302" and "E-Boss 351", fitting either the 302 or 351w block respectively. As of this update, they are only available in a dual-plenum configuration, however are based on Edelbrock's "Air-Gap" design to increase the effective RPM range from 1500 to 6500 RPM. Oh, and in case you're wondering what's so special over a regular cleveland intake - Notice the water outlet - cleveland motors have a dry intake.

Intake Gaskets

You have a few options. Boss 302 intake gaskets have been known to work for the guys running 4v heads. FOr 2v heads you can take 2v 351c gaskets, and cut out water passages. Edelbrock claims that with their new intake manifolds, the answer is to run their intake gasket number 7265, but does not specify what head it's meant to work with, other than they say the port size is 1.52" x 2.16". The 7265 is their standard 351c intake gasket but it appears they are stamping out coolant passage holes that would just be left unused on a standard cleveland installation. If anyone's used a set of these for either a clevor or cleveland motor and can confirm any part of this, please let me know and i'll update this accordingly.

Pistons:

Special pistons are also needed for correct compression and valve clearances. There are two types; flattops and popups, depending on the compression that you want to get. They are available from KB Performance Pistons, reachable at 800-648-7970 (Note: NOT "Keith Black" pistons, "KB" pistons www.kb-silvolite.com). They enable you to use the stock Windsor rod and work with either 2v or 4v heads.

Table of compression ratios:

Heads:

A couple of modifications need to be performed to the heads themselves for coolant passages.

[A] Coolant passages need to be plugged.
[B] 0.80 inch hole must be drilled on each head. Use the intake gasket as a template for these holes.
[C] Remove these alignment pegs.
[D] Use freeze plugs to block these end holes, if the heads have them.

Head gasket and block:

Head gaskets designed specifically for swapping Cleveland heads onto the Windsor block are available from Ford's SVO department at 313-337-1536. There are 3 holes that you must drill in the Windsor block, however, to match up with the Cleveland water passages. Use the head gasket as a template to mark these holes (3 on each side), then remove the gasket and carefully drill them out.

Alternatively, you should be able to run Boss 302 head gaskets. Any notes on this from experience? Let me know and I'll update this page.

Click here for the diagram of where to drill the block.

That's about all that you will need to do this head swap. It's fairly straight-forward and doesn't require machine work besides drilling a few holes.You'll soon be making tons of power with your very own 351 Clevor!!