i noticed, as im sure many of you did, that the new ramjet 350 is based on a 2 bolt block... what gives? i saw a very nice 68 camaro centerfold in CHP one time that had a a 2 bolt, and it was putting out like over 450hp.. closer to 500. my question is.. to what extent can you push a 2 bolt? i've never heard of the mains in any block breaking, but with (distant) plans for a turbo.. should i be sure and have a 4 bolt?

 

I read somehwere that a 2-bolt 350 block can safely handle up to 475 hp, 600 (i think) for a 4-bolt, 850 (i think) for a 4-bolt with splayed caps, and 1000+ for a bowtie block

I don't know if any of this is true.. hell.. can't even remember where I seen it at

 

So what happens when you go over the "allowed" hp regardless if thes numbers are correct or not.. Does the block "crack" fracture what happens?

 

you can also splay cap a 2 bolt and it will be stronger than a stock 4 bolt. becuase of the splayed caps and the 2 bolt blocks actually have more material(stronger) around the caps than the 4 bolts.i am gonna use a splayed 2 bolt for my project lethals10 383 procharged motor.
Dave http://www.geocities.com/maximumvelocityracing

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1997 s10,stock internally 4.3,automatic,3.42's on 235/60/15 drag radials.quickest 8th mile 8.48@79 mph 1.80 60 ft.13.39@103 mph on my g tech.
LIFE IS SHORT, SPRAY HARD!

 

go with the 2 bolt if you can get it at a good price....just get splayed caps. **** by the time you get a turbo....she might need a rebuild!!! My 400s gonna have splayed 2 bolt. lataz

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Rick
90 Camaro RS 305 TBI
400 small block, Hooker 1 3/4 LTs, Random Tech Cat, Hooker aero chamber cat back on the way!!
TH700-R4 with Trans-Go shift kit (corvette servo here...but not installed yet)
MacEwen Motorsports White Gauge Overlays
14" K&N X-Stream Open Element
GTS Headlight and Taillight covers
5% Limo Tint all around
Classic White Chevy Bowtie sticker on rear window
http://www.geocities.com/esvalenz

Man if my camaro were a rice-rocket all those mods would give me what...easily 50-60 hp!!!

"Just because I've done it, doesn't mean I knew what I was doing!" - Me

 

when you go over the limit....the crank deflects too much and sh*t catastophicaly breaks. I remember reading 600 hp was the magic # somewhere, I think it was car craft or HOT ROD- I have 2 bolt mains.

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91 RS W/carbed 350, Vortec heads, performer rpm, Comp cams Xtreme energy 226/230 duration and .477/.480 lift. BFG Drag radials. 3.42 posi,Corvette servoed 700r4, ****ty stock converter. Edelbrock TES, 3inch cat, flowmaster with single 2.5 inch exit.
13.24@104

 

i've heard the term splayed before.. what exactly is it?

 

splayed caps have the 2 outter bolt holes at an angle, this lets them thread into a thicker area in the web of the block. i have a 4 bolt 350 block laying in front of the garage with a cracked #4 main cap. personally i'd worry more about quality machine work than 2 or 4 bolt mains ,and i'd use arp studs.

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ICON Motorsports

1st & 3rd

 

Limitations? Well how far do you want to go? What you can do to modify blocks for strength is almost limitless. But for lower rpms, you wont need to worry about four bolt mains. But if your constanly running 6000-7000 rpms, then you'd want to think about it. If you put out alot of torque, then get a main girdle. What this does is reinforce the mains by means of basically a reinforcement bar onto the caps. You need to have special studs that protrude further out, and this girdle bolts on to them.

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'82 Firebird, dead stock, 9 bolt disc rear, over 200,000 miles and still going strong, more to come...
http://www.spinfrenzy.com/stingerssx...easures.html#4

 

generally 2 bolts are good enough for even the most radial street engine 4 bolts are just stronger(except on some 400's) and are extra security for high horse power engines.

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1989 firebird formula

Mods: converted from T.B.I. to a carburator 305 to a 350. Flowmater exhaust,hedman shortie hedders,202 heads,350 horse cam,bored.40 over, Edlebrock torker2 intake.

Future mods performer rpm air gap intake (polished) and 600 edlebrock carb, comp roller cam, and way better headsa 400 defintely in the works!

 

I agree with all the posts above. Personally, if you THINK you need a 4 bolt, you are better to start with a 2 bolt and get it splayed...its the strongest of all.

 

alright... sounds like some reassuring info guys, i just got worried for a minute when i saw that GMPP was offering their ramjet 350 with a 2 bolt main,, i mean, its got a full roller drivetrain, and brand new design as for the intake, and its sitting on a 2 bolt!?! what gives? its NOT that much more to have a 4 bolt block.. ESPECIALLY relative to the price of that engine. anyways, yea, i dont think ill be quite as hesitant as before about 2 bolts, will just make sure to haev those few reinforcements in place