converting 2 bolt to 4 bolt

[markss28]

I have a 2 bolt in my car right now and I have all the parts to build a new 383 stroker with crank , rods, pistons and all. All I need is a 4 bolt but they seem to be very hard to find or a bit pricey. I have seen on line a few engines converted to a 4 bolt and was wondering if that was a good option.

Will it have the same stregth as a 4 bolt or just a bit stronger then a 2 bolt?

[QSPres]

I have a 2 bolt in my car right now and I have all the parts to build a new 383 stroker with crank , rods, pistons and all. All I need is a 4 bolt but they seem to be very hard to find or a bit pricey. I have seen on line a few engines converted to a 4 bolt and was wondering if that was a good option.

Will it have the same stregth as a 4 bolt or just a bit stronger then a 2 bolt?

2 bolt blocks are stronger. They just have less clamping force on the crank.


I say "F" the four bolt blocks. Buy a set of splayed main caps and have your machine shop drill and tap your block for them. I did that to several Pontiac motors and they all ran great.

[70TWO NOVA]

Splayed caps on a stock 2-bolt block is the way to go. The 2-bolt blocks have much thicker webbing than the 4-bolt blocks.

[markss28]

I heard that same thing years ago and just wanted to confirm it. I will be checking with the machine shop to see what it would cost.

[2muchTA]

I heard that same thing years ago and just wanted to confirm it. I will be checking with the machine shop to see what it would cost.

I converted my 2 bolt to a 4 bolt with splayed caps. I couldn't be happier that I did it.

For comparison... I had my block cleaned, the caps installed (plus the price of the caps) and new cam bearings pressed in and it cost me just shy of $700. I don't know if I payed too much or too little but it's a starting point.

[cj422man]

Hey guys im a newbe here and thought i would let you know that i had my 400 converted to Eagle splayed mains, Moroso filler up to the plugs, new cam bearings, alignd bored and honed, and clearanced for 3.875 crank, plus the main caps and it was cnc done plus painted and cost me $510. 4 bolt 400 blocks are the weak ones not the 350. if 350 4 bolt were weak then they wouldnt have been in trucks. i own 6 350 4 bolts and 1 2 bolt also 2 283 blocks and 2 305's want to buy any??? if you would like some pics of the main caps installed shoot me an email i have a lot of pics of mine. and i can scan a copy of my bill for the 400. check out www.rmcengine.com for the videos of the cnc machines. mine was done on the V30. go to www.montecarloss.com/SSThunder/SBCinfo.html and at the bottom of the page it gives hp recommendations for each block. im not trying to step on any toes, just my 2 cents. thanks

[cj422man]

here is my 400 http://img297.imageshack.us/img297/5647/jul1593ti1.jpg

[crazycarl]

Do the two bolt block and have it machined for the splayed four bolt caps. The caps aren't necessarily stronger, they just flex less. Think about it, the more holes you have in something, the weaker it is, but the less points you have holding something down, like a crank, the more it will flex. A splayed cap spreads the stress of the spinning crank over a wider surface area giving you the best combination possible.

[markss28]

Thanks for the info, but I found a 4 bolt bored and stroked it and am not assembling the engine.

[rocketman]

Splayed is the only way to go when doing a convertion

[J-440]

Have you thought of a stud girdle? 1/4" thick plate that ties in the mains with the block, ARP studs, and acts as a crank scraper. For about $350 and will sustain around 900 horses. Just another option.

[kevin9412]

Hey guys im a newbe here and thought i would let you know that i had my 400 converted to Eagle splayed mains, Moroso filler up to the plugs, new cam bearings, alignd bored and honed, and clearanced for 3.875 crank, plus the main caps and it was cnc done plus painted and cost me $510. 4 bolt 400 blocks are the weak ones not the 350. if 350 4 bolt were weak then they wouldnt have been in trucks. i own 6 350 4 bolts and 1 2 bolt also 2 283 blocks and 2 305's want to buy any??? if you would like some pics of the main caps installed shoot me an email i have a lot of pics of mine. and i can scan a copy of my bill for the 400. check out www.rmcengine.com for the videos of the cnc machines. mine was done on the V30. go to www.montecarloss.com/SSThunder/SBCinfo.html and at the bottom of the page it gives hp recommendations for each block. im not trying to step on any toes, just my 2 cents. thanks
hi my name is kevin,i own my own mackine shop,i do also do line boring,and block decking,cylinder boring,and honing,and cylinder heads,and much more if you would like some help with this call me anytime i would be glad to help you...toll free (866)249-4712 my shop is located near magnolia,tx.i look foward to talking with you kevin.

[kevin9412]

2 bolt blocks are stronger. They just have less clamping force on the crank.


I say "F" the four bolt blocks. Buy a set of splayed main caps and have your machine shop drill and tap your block for them. I did that to several Pontiac motors and they all ran great.hi my name is kevin.i own a automotive machine shop near magnolia,tx its kevins automotive machine shop,inc.we do allot of line boring,rod resizing,and also cylinder boring,and complete cylinder heads.if there is ever anything i can help you with call me at (866)249-4712