Hi, I'm building a 383 for my IROC and I'm wondering if my 2 bolt block will be enough. My machinist is trying to sell me on a 4 bolt block but I'm not sure I will need it. Any thoughts? I've got a late model 1 peice rear seal roller block. Have forged rods, pistons, and crank. ARF heads, 219 cam, SLP headers and a 100 HP shot of No-2

 

IIRC a 2 bolt with splayed main caps is good for almost 500HP. Anything over that would warrant something different. What is your estimate with your combo for HP??? I assume somewhere around 500ish with the 100 shot??? How often would you run the juice???? Just for track or on the street too???

EDIT: Also check your PM's about the STB

 

Prolly closer to 800hp.

-- Joe

 

No-2, Not often. 800 hp Really? That's with splayed caps not the 2 bolts right? Should I convert it to 4 bolts? I read a post here on 3rdgen where a guy drilled, tapped and installed his own 4 bolt caps and then had it line bored by a machine shop when he was done. Strong and a heil of a lot cheaper.



Razor: Will email you.

 

Tim Sifford (aka Traxion) who ran low 11s still ran with the original bottom end. And ALL 327s (which so many people fondly remember) were 2 bolt.

It really depends on the HP you plan on building. 4 bolt is nice, but it is not necessary unless you plan to make over 400 HP; and I know a number of people who will argue that you can go higher too.

And, if you are going to make that much HP that you MUST have 4 bolt (or splayed), you probably should be looking at a different block also (i.e. older high nickel block or non-production/aftermarket).

 

I think the 2 vs 4 is the least of your concerns. The iron caps will crack long before you pull a bolt out.

-- Joe

 

Tim didn't race 5-10 passes every weekend for 5 years either though. I imagine Tim's setup would have eventually blown up. But it still wouldn't have been the 2 bolt mains that went.


-- Joe

 

Anybody else care to chime in?

 

It sounds like you have a quality rotating assembly, and if you trust your machinist, take his advice and go with the 4 bolt block. The older "seasoned" blocks do have a higher nickel content, and IMO would be the better choice. The 1 piece seal later blocks are a bit weaker, especially when you start adding some power. And believe it or not, the 2 bolt vs. 4 bolt is not the issue. We have had many 2 bolt blocks that were studded, and held up to some serious abuse. If and when they crack, its not ushually in the main area. You got expensive parts, why bolt them to a weaker block?...Tom


Im sorry, are we talking about an older 4 bolt block, or is the machinist trying to sell you an aftermarket?

 

IIRC a guy in hotrod had a stock TPI bottom end with NOS and superram that had over 1000 passes on it . It was running 10's too.

 

Well, The parts were cheap because I shop for bargains, Barter, ebay and port stuff in exchange for parts. The older block is not an option. My crank is for a one piece rear main seal. So it will be the 2 bolt block I have or a late model 4 bolt block out of a truck. I had a thread going on here when I started this project called "How to build a 383 on the cheap" I have followed that plan pretty closly. I have been thinking about drilling, tapping and installing my own slayed caps and then just having it line bored. Good no?

 

Since they are both late blocks. use either one. Use the 4 bolt as it is, or use the two bolt, and just use ARP studs, instead of bolts. You will save money on the splayed option. Im not sure of the price of the studs, but I believe they will be less than the machining operation. Ive used 2 bolts with studs, and never had a problem. Lots of 500 h.p engines with 2 bolt mains out there....Tom

 

I have just an arp studded two bolt and its held up well so far. The motors between 400-550 hp. Havent gone back to the dyno yet.

IMO if you can afford it get the 4 bolt. I couldnt so just studded mine.

 

well i will be running close to 500hp n/a and a 150 shot. standard l98 2 bolt roller block. we shall see what happens...

 

Hey ! That's me too. When will you be on the street? I'm shooting for May. Maybe we should have a contest to see who can post the best times without catastrophic engine failure.

 

yea lol. i cant really hit it anyway yet because of my t-5 and 10 bolt but when those get replaced its all bad for that block