I am getting ready to build a 350 for my Firebird. I'm going to put on an Edelbrock performer package to make around 400 HP with this block, with the possibility of NOS later on down the line. Now my question is this. My friend has an aboundance of 350's that are 2 bolt mains, but none that are 4 bolt. Will a 2 bolt main be able to handle the close to 400 HP I'm expecting or should I go with a 4 bolt? He thinks I should be fine with just a 2 bolt, but I'm questioning that. Does anyone have any idea how much HP a 2 bolt is good for? Thanks for your time!

 

HP doesn't kill a block, RPM and maladjusted components do. If you stay below 500hp, and under 6500 rpm, you will be fine. I know a lot of people have different opinions, but I would not fear building a 500hp 2-bolt engine. You just have to make sure the clearances are correct, and timing is right. IF you still want a 4-bolt, take the 2-bolt and have splayed main caps put on, and the appropriate holes drilled. This will be stronger than the production car/truck 4-bolt block.




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Joshua Johnston
1991 Z-28


350, T-5, K&N, Ported Vortec heads, Edelbrock RPM, Holley 750 D.P., HEI, 11.07:1 CR, Comp Cams Roller-.510"/.520"-282*/288* dur., Shorty Headers, Dual 2.5 Exhaust,Dynomax Bullet Mufflers, T&R Motorsports custom air intake

 

Staying below 6500 RPM, shouldn't be a problem. That's common sense. Would having my engine balanced help longevity? Or is that not needed?

 

I have only built 9 engines, so I am not as experienced as some people here, but I have not had 1 of them balanced. It is highly recomended, but the engine would run fine if you didn't. And whats this common sense stuff about kepping it below 6500 rpm!!! I have buzzed some of mine to 6800 w/o problems. Its an addiction to hearing that ungoddly (sp) scream of power!!!




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Joshua Johnston
1991 Z-28


350, T-5, K&N, Ported Vortec heads, Edelbrock RPM, Holley 750 D.P., HEI, 11.07:1 CR, Comp Cams Roller-.510"/.520"-282*/288* dur., Shorty Headers, Dual 2.5 Exhaust,Dynomax Bullet Mufflers, T&R Motorsports custom air intake

 

BALANCE IT! use the two bolt and you will be fine.

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1982 Z28:355,4 Speed,Lots of bolt ons

 

Balanced and use studs in the mains then get the block line honed.

My BBC is only a 2 bolt but has studs. Using the studs will make it as strong as a 4 bolt. It just takes a bit more machine shop work.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation with a typical race day over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

I'll definately balance it then. Thanks for the info.!