I am just curious of what you think the redline is for a 2 bolt block. I would like to think that I might be able to run a 6500 rpm cam with my stock 2 bolt. Just curious if it can handle it or do I really need to step up to a four bolt. The engine would have less than 500hp probably 450 with a 383 motor. Thanks.

 

It Should be fine reving up to the 5500 range. A 4 bolt main is just some added insurance, but ive never seen a 2 bolt 383.
BTW
Middleton makes some high strength 2 bolt caps that you might want to invest in if you plan on stroking this block.

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If you really want to be original slap in a TURBO DIESEL!

 

Or you could always take it to a machine shop and have them make it a 4 bolt. Don't know how much that would cost, though.

Vman

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1969 Camaro Sport Coupe
383, 700R4, leather, everything black but the lights

Previous owner of an 89 RS Camaro
2.8L V6, 700R4

 

2 bolt mains can handle 600hp at 6000rpm.
I was asking my mechinest about building a 383 with 4bolt mains and he told me that 2bolt mains will work fine as long as you don't rev it too high.

 

a two bolt block is pretty much safe to 7000rpm, but i wouldn't say much over 6000 with a 383. the longer stroke adds alot of extra stress. i'm currently finishing mine with a two bolt block, but i went with 6 inch rods to lighten the bottom end along with the other goods of a 6 inch rod. this will allow for a few hundred extra capability, but at next teardown it's getting splayed.

 

GTA,

I'd be more concerned about the rods and rod bolts at that kind of continuous RPM. The main caps can be studded with thread inserts for more bolt strength, and/or you can install a girdle to stiffen the entire lower end (like a heavy-duty windage tray).

The cast crank and rods should be balanced, and high quality rod cap fasteners should be used at that RPM. You'll also need to control the lifters with the correct springs or a rev kit.

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Later,
Vader
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"What a Day..."
Adobe Acrobat Reader

 

I'm dumb, What is all the 2-bolt 4-bolt thing? Where are these bolts at?

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'87 Trans Am:
(Engine)
305 TPI
180 Degree Thermostat
JET Fan Switch
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment & Cat.
(Stereo)
Full Kenwood Excelon System

 

On the main bearing caps of an engine theere are bolts that hold it on. The chevy small block can have One bolt (two total) on each side of the crank or two bolts (four total). The Four bolt caps can obviously handle more force and dissapate it over a lrger area thus handling more stress. It is not necessary for street engines however because they don't rev as high as race enignes.

 

l think l remember a q&a session in Hot Rod or some other magazine that said that older 4 bolts arent necessarily stronger than 2 bolts because they tended to get stress cracks between the two side by side bolt holes. At the time l had a V6 so l didnt pay as much attention as l would right now.

Clayton

 

Lingenfelter sells 2-bolt 383 short blocks in their catalog. What does that tell you about the strength of a 2-bolt?

 

A 2 bolt main block should work fine. A couple of things though. Use new fasteners preferably a main stud kit. This will help strengthen the bottom end. The weight of the pistons and rods has a lot to do with the ability of a 2 bolt being able to rev high and not break. Go with the lightest pistons you can afford and the lightest rods you can afford and make sure it's all balanced, then you should have no problems. Also you might want to go with standard wrist pins instead of thin wall. Even though they weigh less they can flex and cause problems.

 

Thanks for the info. Now I can follow you guys. Carry on

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'87 Trans Am:
(Engine)
305 TPI
180 Degree Thermostat
JET Fan Switch
TB Bypass
Accel 300+ 8.8 Racing Wires
Accel Super Coil
Bosch Platinium Plugs
Custom Ram Air with K&N
Removed Emissions Equipment & Cat.
(Stereo)
Full Kenwood Excelon System