All I can say is that my 454 with 9" street tires and about 80lbs more than your can breaks them loose at 35mph and sometimes at 40mph going WOT. And it's not like it's that radical of a build either.
Big Block Quandry
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With a forged crank and decent aftermarket rods, a 496 revs just as fast as the 427, actually even faster when its in gear and moving the car rather than just being free revved in neutral.....reason is the more power you make, the faster the car accelerates and thusly the faster the engine gains rpm.
that old wives tail about 302 and 327 SBC, and 427 BBC being "quick revver's" stems from the fact that in the days when those were the new technology engines, comparing them to Y-block Fords, Flatheads, Chrysler PolyHead, Ford 390 FE's and other typical passenger car designs made the Chevy's seem like quick revvers. But in truth RPM gain depends entirely on how fast you can move the mass of the vehicle.
how it free-revs in neutral means about as much as how fast you can pedal your bike with the back tire off the ground
:mwink::mwink:
As far as blowing the tires off on the road....you've got a brain connected to your foot....just use it.
When you've got real power you don't need to mash it clear to the floor just to get around somebody.
As far as that G-body goes....I hope you have more than a stock 7.5" 10-bolt in there, because real power will tear it up right quick if it hooks up at all....plain street tires usually won't hook well enough to break it, but stickier street/strip or autocross tires will.
Either the 427 or a 496 will be a several levels of magnitude improvement over the small BBC you have now, a real eye opener about cubic inches and how bore diameter impacts head flow for you.
that old wives tail about 302 and 327 SBC, and 427 BBC being "quick revver's" stems from the fact that in the days when those were the new technology engines, comparing them to Y-block Fords, Flatheads, Chrysler PolyHead, Ford 390 FE's and other typical passenger car designs made the Chevy's seem like quick revvers. But in truth RPM gain depends entirely on how fast you can move the mass of the vehicle.
how it free-revs in neutral means about as much as how fast you can pedal your bike with the back tire off the ground
:mwink::mwink:As far as blowing the tires off on the road....you've got a brain connected to your foot....just use it.
When you've got real power you don't need to mash it clear to the floor just to get around somebody.
As far as that G-body goes....I hope you have more than a stock 7.5" 10-bolt in there, because real power will tear it up right quick if it hooks up at all....plain street tires usually won't hook well enough to break it, but stickier street/strip or autocross tires will.
Either the 427 or a 496 will be a several levels of magnitude improvement over the small BBC you have now, a real eye opener about cubic inches and how bore diameter impacts head flow for you.
Yeah, the factory posi's are weak, the side and spider gear teeth are real fragile.
Care to share how you got 31 spline axles into a 7.5"?? No one makes them, or a posi or spool to fit them, and that size axle won't even fit through the carrier bearings on each end of the differential for that matter.
Biggest axles that will fit through the bearing are 28 spline, up from the factory original in your G-body of just 26 spline....but even then, with 28 spline axles the axles aren't the problem....you get this down into the high 12's at the strip and it's going to start peeling ring and pinion teeth off(pinion stem flexes due to small size and gear mesh goes all to crap and crunch ), and there ain't no heavy duty fix for that except an entire rear end swap to something that will handle the power....12-bolt, 8.5" 10-bolt, Ford 9", custom Dana 60.
There's a reason GM put the 8.5" in turbo Buick G-body's, looks like you're about to find out why with the new engineain:
Care to share how you got 31 spline axles into a 7.5"?? No one makes them, or a posi or spool to fit them, and that size axle won't even fit through the carrier bearings on each end of the differential for that matter.
Biggest axles that will fit through the bearing are 28 spline, up from the factory original in your G-body of just 26 spline....but even then, with 28 spline axles the axles aren't the problem....you get this down into the high 12's at the strip and it's going to start peeling ring and pinion teeth off(pinion stem flexes due to small size and gear mesh goes all to crap and crunch
), and there ain't no heavy duty fix for that except an entire rear end swap to something that will handle the power....12-bolt, 8.5" 10-bolt, Ford 9", custom Dana 60.There's a reason GM put the 8.5" in turbo Buick G-body's, looks like you're about to find out why with the new engine
ain:
The axles are from superior. I bought them back in 2003. They were supposed to be a direct replacement for a 7.5 26 spline rear. However when I got them they either had 31 or 33 teeth on them. When I ordered the posi from auburn I asked if I could get gears to fit those axles and they said no problem I put it all together with new bearings & seals and everything fit like a glove. I don't know if you can even get those axles anymore. Another thing I did was use a 3:08 and lower carior? and put 3:42 gears on it. It has a thicker ring gear that way. I have also heard that this rear will not hold up to 12's & lower. Thinking about a strange with the new engine.Yeah, the factory posi's are weak, the side and spider gear teeth are real fragile.
Care to share how you got 31 spline axles into a 7.5"?? No one makes them, or a posi or spool to fit them, and that size axle won't even fit through the carrier bearings on each end of the differential for that matter.
Biggest axles that will fit through the bearing are 28 spline, up from the factory original in your G-body of just 26 spline....but even then, with 28 spline axles the axles aren't the problem....you get this down into the high 12's at the strip and it's going to start peeling ring and pinion teeth off(pinion stem flexes due to small size and gear mesh goes all to crap and crunch
There's a reason GM put the 8.5" in turbo Buick G-body's, looks like you're about to find out why with the new engine
3
If you are talking about rotating assembly clearances, then the connecting rod nuts(if thru-bolt) or bolt head(capscrew type rod) may have clearance problems with the oil pan rail area of the block.....easy to fix, slight 1/16-1/8" groove ground to clear the rod in the oil pan rail, and the stroker oil pan with clearance flats stamped in the pan rail.
you will also have to put similar notches at the bottoms of the cylinder barrels, near the can tunnel, depending on which connecting rods are used.
You'll need to do a trial assembly, one cylinder at a time. to find all the locations to grind. SBC strokers have to go through the same process.
This pan image will give you a good idea what this is, block needs to look something like that at the oil pan rail.
![]()
Block images:
https://www.bing.com/images/search?...&selectedindex=13&ajaxhist=0&vt=0&eim=0,1,2,6
![]()
![]()
Hot Rod mag article that will help you a lot.
https://www.hotrod.com/articles/how-to-clearance-big-block-chevy-for-stroker-crank/
you will also have to put similar notches at the bottoms of the cylinder barrels, near the can tunnel, depending on which connecting rods are used.
You'll need to do a trial assembly, one cylinder at a time. to find all the locations to grind. SBC strokers have to go through the same process.
This pan image will give you a good idea what this is, block needs to look something like that at the oil pan rail.
Block images:
https://www.bing.com/images/search?...&selectedindex=13&ajaxhist=0&vt=0&eim=0,1,2,6
Hot Rod mag article that will help you a lot.
https://www.hotrod.com/articles/how-to-clearance-big-block-chevy-for-stroker-crank/
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