does it really matter 4bolt or 2bolt main? HELP FAST

kiln · #1 (**permalink**) 05-30-2002, 08:48 PM

Im currently lookn at buying a 429/460 Ford big Block.. Should i find a 4 bolt main block or is the 2 bolt main fine?? can anyone clarify this for me.. Im ready to buy one.. I just wanna make sure I buy the right block

Ryan

bmalone · #2 (**permalink**) 05-30-2002, 08:50 PM

Ryan:

Two-bolts okay up to 600 HP.

Bill

427sharpe · #3 (**permalink**) 05-30-2002, 09:32 PM

2 bolts are fine, but if you find a 4 bolt it will be cheap insurance. 4 bolt blocks are rare for the 429 series, the SCJ's being the only production version. FoMoCo has an iron 4 bolt now in the marine catalog (same one in the hi-perf catalog too, I think).

Tom Wells · #4 (**permalink**) 05-31-2002, 06:09 AM

Ryan,

There are more possibilities.

On some 429/460 2-bolt blocks, the main bearing web area extends out to the pan rail, is machined flat and has constant thickness. Others have a slight "dip" in that area, not fully machined, and with a bit thinner main bearing web. These second ones are the ones I believe Bill refers to above as "okay up to 600 HP".

Couldn't quickly find pix of these differences but they are obvious and should be familiar to any 385-series FoMoCo engine builder.

I DID find the following web site where you can buy aftermarket 4-bolt caps for the first type (thick main bearing web) of 2-bolt block and also the original blocks:

http://pro-gram.com/catalog/catalog....=program.setup

Have fun!

Tom

PS: Here's a site that has pix:

http://fordifiedracing.homestead.com/460tech.html

Note the SCJ has the flat rail. There ARE 2-bolt blocks having the flat, thick main webs for #2, #3 and #4 that can be drilled and tapped to accept the 4-bolt aftermarket caps. I don't know the clues to finding them offhand - sorry.

Also Moroso and others may sell the add-on "splayed" type caps...

Then again, I could be wrong - I can't remember whether I've made my mistake for this year or not!

cobrashoch · #5 (**permalink**) 06-02-2002, 08:05 PM

Kiln- As a rule if it's on a carb and streetable the 2 bolts are are O.K. You can also add a Blue Thunder steel main girdle (cleap) to help beef things up and a stud kit will help to. The block that has thick mains has the same casting numbers that was used on 429 - 4 bolt blocks and guys scower the junkyards to find them. They were used in trucks I think. There is several aftermarket 4 bolt conversions on both styles of 2 bolt blocks but be forwarned they all require machining on the block as far as I know. If you use a main girdle a custom oil pan has to be also used.
cobrashock

SFfiredog · #6 (**permalink**) 06-02-2002, 11:00 PM

the block you are refering to has the casting # DOVE. This block is the same type as the 2 bolt 429 CJ. I have found these blocks were used in marine applications, along with the spot faced CJ type rods. It is the best 2 bolt block to use if you can find one. I would recomend sonic checking though because the last DOVE block I had could only be bored .030 safely. The sonic check mapping showed the cylinders were thick at the bottom of the bore but thin at the top. Sort of the opposite of what you would want.

HTH,
Mike

rlearp · #7 (**permalink**) 06-03-2002, 05:23 AM

Four bolt mains are mainly bragging rights in the beer hall, to all but the real racers. Plently of folks running 2 bolts a high hp levels, there is no "real" cut off. A switch does not get tripped at xxx hp and after that the block will most certainly self-destruct.

Most of it will be your useage patterns that will determine how the block will do. Girdles are cheap, I'd go with one of those for a little peace of mind.

Ron