Reply to "What cleveland block to use for HP engine?"

> What is the best cleveland block to use for a high performance engine? I'm
> not thinking of an aftermarket block. Any special casting number to look for?
> 2 bolted or 4 bolted?

2 or 4 bolt blocks are essentially the same, except for the main caps.
The only blocks that are substantially different are the XE-192540 casting
race blocks. Only a few hundred were made specifically to address the
problems (cracked main webs and cylinder walls) 351C blocks were experiencing
in professional racing. Often referred to as the "NASCAR" block as many were
used in NASCAR competion. Also used in Pro Stock drag racing. These blocks
carry an XE casting number prefix (e.g. XE-192540), thick, non-contoured main
bearing webs, one inch thick block skirt (pan rail), heavier, high nodular
iron four bolt main caps, and usually 0.165 inch minimum thickness cylinder
walls. These were 4 bolt main blocks with non-Siamese bores. Unlike
aftermarket race blocks, deck height, bearing sizes, bell housing bolt
pattern, oiling system, and oil pan pattern are all identical to a standard
351C block so all 351C parts can be used. Since Ford had ceased production
of the 351C in the United States, the XE race blocks were cast and machined
in Australia. The first batch were manufactured in 1975. These blocks were
available over-the-counter, if you knew enough to ask for the right part
number and had the cash. They were listed under the catalog part number
D1ZZ-6010-T and were quite expensive for the time, about $1500 in 1976.
Some people believe that they originally designed for use in Australian Ford
trucks but that is not the case (Aussie Ford trucks used plain old open
chamber 2V engines with 2 bolt main blocks). The XE blocks were specifically
designed for racing use. The blocks were completely machined, except for the
cylinder bores which were semi-finished, being rough-bored at 3.990". A
number of these blocks were shipped to Holman and Moody and Gapp and Roush.
Holman and Moody used to list these blocks under the part number D6HM-6010-1.
A second batch was cast circa 1982. They were similar to the first batch
with some minor revisions. When Ford (U.S.) decided to get back into racing
in early 1980's with the SVO parts program, they placed an order to cast and
machine a second batch of XE blocks. These were manufactured during 1982 and
1983. There were quite a few of the second batch that didn't meet minimum
specs with respect to core shift and other defects. Some of these blocks
were subsequently transferred to the standard machining production line and
were sometimes fitted with two bolt main bearing caps (depending on when they
were discovered to be defective) for use in a standard passenger car engine.
The blocks that passed inspection were originally listed in the U.S. SVO
catalog under the part number M-6015-A3.

Pictures of my second batch XE block (the one I sold to Kaase for the Engine
Masters Competition) are here:

http://www.bacomatic.org/gallery/dan-ausclv

Note the Gapp & Roush straps on the caps were added later.

Beware of people trying to pass of standard Aussie blocks as XE blocks.
I've owned several U.S. 2 and 4 bolt main blocks, as well as Aussie 2 bolt
main blocks and a couple of the XE blocks. One my bathroom scale, the Aussie
2 bolt main blocks weigh the same as their U.S. counterparts. The XE is
considerably heavier.

Dan Jones