Need Advice
Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 20
Likes: 3
Need Advice
I built and installed a 650HP gen 1 427 SBC in my 73. I've spent 5 grand upgrading everything from the tranny to the spindles with chromoly and 4130 components. I'm left with one cast iron piece, the flange on the outer end of the half shaft. The car will see weekend bracket racing using 28-10.50 DOT tires. I can't find a 4130 flange. Tom's used to sell them, but no longer. Does anyone else make them? Are they even required for this situation?
Drifting
Joined: Aug 2022
Posts: 1,309
Likes: 379
From: Ruskin, FL
I built and installed a 650HP gen 1 427 SBC in my 73. I've spent 5 grand upgrading everything from the tranny to the spindles with chromoly and 4130 components. I'm left with one cast iron piece, the flange on the outer end of the half shaft. The car will see weekend bracket racing using 28-10.50 DOT tires. I can't find a 4130 flange. Tom's used to sell them, but no longer. Does anyone else make them? Are they even required for this situation?
Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 20
Likes: 3
Passing tech isn't my main issue. The car will spend 99% of the time as a street rod. If I decide to add some N2O, I'll be at 800HP and 750# TQ and that half shaft flange looks to me like it will be the weak link in the chain.. I simply don't know if that cast iron piece can hold up. I've seen what happens when the outer end of that shaft breaks loose! I know that if you race, you will break something sooner or later. I'm just trying to make it later than sooner.
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,900
From: Connecticut, USA
What are you running for a diff?
Were you looking for Tom's billet 1350 drive flanges? I have not seen those in decades. You might break the joint before you break the flange. Of course, if you have a 10 bolt than you may be looking at other concerns once you apply your power.
Were you looking for Tom's billet 1350 drive flanges? I have not seen those in decades. You might break the joint before you break the flange. Of course, if you have a 10 bolt than you may be looking at other concerns once you apply your power.
Drifting
Joined: Aug 2022
Posts: 1,309
Likes: 379
From: Ruskin, FL
Passing tech isn't my main issue. The car will spend 99% of the time as a street rod. If I decide to add some N2O, I'll be at 800HP and 750# TQ and that half shaft flange looks to me like it will be the weak link in the chain.. I simply don't know if that cast iron piece can hold up. I've seen what happens when the outer end of that shaft breaks loose! I know that if you race, you will break something sooner or later. I'm just trying to make it later than sooner.
Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 20
Likes: 3
The diff. is the corvette IRS. w/3.70 gears. Fed by 3" MW driveshaft w/ forged ends. Diff. has 4130 stub shafts, new posi with 400# springs and carbon fiber clutches from Duntov. 3" MW half shafts. Global West tubular trailing arms w/spherical bearings and 4130 spindles set to .0015 endplay.
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,900
From: Connecticut, USA
The diff. is the corvette IRS. w/3.70 gears. Fed by 3" MW driveshaft w/ forged ends. Diff. has 4130 stub shafts, new posi with 400# springs and carbon fiber clutches from Duntov. 3" MW half shafts. Global West tubular trailing arms w/spherical bearings and 4130 spindles set to .0015 endplay.
MW 1/2 shafts are 3" x 083", the 1350 Spicer would be the weaker link.
Whose outer axles are you running- 17 or 31 spline.
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Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 20
Likes: 3
Big thanks to GTR1999! To answer his questions, the posi was from Duntov. The local guy that set it up said it was a Yukon. He and his father have done work like this for 40 years and are very well spoken of. He told me that he set the posi up (shimmed) to be where it should be. What he told me sounded just like what Tom's showed in his videos. The spindles are from Duntov and are 17 spline. I'm unaware of the carbon fiber issue you spoke of. Never ran them before, thought it would be a nice upgrade.
The diff. is what it is. It has to be stronger than it was. My concern about the half shaft flange seems to be answered. It sounds like it will not be the weakest link and I can run them instead of searching for forged ones.
The diff. is what it is. It has to be stronger than it was. My concern about the half shaft flange seems to be answered. It sounds like it will not be the weakest link and I can run them instead of searching for forged ones.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,443
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
The stock outers and inner yokes are a weak like. I was running 10 inch Goodyear slicks and years of bracket racing. The outer axles never snapped , but it scared me when I saw that they had actually rotated a whole spines width. Back then I just bought Tom's outers.
IMO instead of a heavy Vette. Buy dragster or some light drag car. I had a port injected two stage intake for SBC. I ran a 125 N2O shot in 1 gear and an additional 250 shot in second and third. EVen stripped down to 3000 lbs with a full cage the power to weight ratio is bad. The weight x-fer of a street vehicle is compromised. You have to mod so many things. Run SFI everything clear down to the drine line safety hoop.
IMO instead of a heavy Vette. Buy dragster or some light drag car. I had a port injected two stage intake for SBC. I ran a 125 N2O shot in 1 gear and an additional 250 shot in second and third. EVen stripped down to 3000 lbs with a full cage the power to weight ratio is bad. The weight x-fer of a street vehicle is compromised. You have to mod so many things. Run SFI everything clear down to the drine line safety hoop.
Tech Contributor
Joined: Aug 1999
Posts: 15,114
Likes: 3,900
From: Connecticut, USA
Big thanks to GTR1999! To answer his questions, the posi was from Duntov. The local guy that set it up said it was a Yukon. He and his father have done work like this for 40 years and are very well spoken of. He told me that he set the posi up (shimmed) to be where it should be. What he told me sounded just like what Tom's showed in his videos. The spindles are from Duntov and are 17 spline. I'm unaware of the carbon fiber issue you spoke of. Never ran them before, thought it would be a nice upgrade.
The diff. is what it is. It has to be stronger than it was. My concern about the half shaft flange seems to be answered. It sounds like it will not be the weakest link and I can run them instead of searching for forged ones.
The diff. is what it is. It has to be stronger than it was. My concern about the half shaft flange seems to be answered. It sounds like it will not be the weakest link and I can run them instead of searching for forged ones.
