When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Does anyone know if the bolt pattern on an LS/Vortec 3 bolt cam/timing sprocket is identical to a SBC/BBC or not?
The flat nose SBC and BBC are the same bolt circle pattern. The later model SBC and BBC step nose bolt pattern are the same as the LS cams. Some have a metric thread and some have American std thread but the bolt circle is the same in the later models.
The flat nose SBC and BBC are the same bolt circle pattern. The later model SBC and BBC step nose bolt pattern are the same as the LS cams. Some have a metric thread and some have American std thread but the bolt circle is the same in the later models.
Awesome info! Thank you.
I'm a little unsure about the two distinctions you mention. I'm looking to cam drive a fuel pump and the the description says fit's small and big block chevy. Do you foresee any reason this hex adapter wouldn't bolt right on top of an LS cam sprocket too?
I'm a little unsure about the two distinctions you mention. I'm looking to cam drive a fuel pump and the the description says fit's small and big block chevy. Do you foresee any reason this hex adapter wouldn't bolt right on top of an LS cam sprocket too?
I don't think it will it's for a SBC and a BBC.There is no step on the early models and no thrust plate. That piece is for the early models.
I don't think it will it's for a SBC and a BBC.There is no step on the early models and no thrust plate. That piece is for the early models.
Thank you Kip, for taking the time to help me out. It's guys and companies like you/yours that get my business. I will be calling you in the next month or so, when it comes time to narrow down a cam for this build. I just haven't had luck getting this level of customer (or future customer) service from the large companies.
Comp's response to the same question:
Not that I know of, Seth. While the bolt pattern could possibly be the same, the camshafts are vastly different.
And a great response from Good Vibrations Motorsports, who sell the adapter, but deal primarily in blown alcohol MFI big blocks:
Unfortunately, that is not something we can advise you on as those motors we do not deal with. What we can do though is match up the bolt pattern on your cam gear and see if it matches our hex drive. The bolt pattern on our drive is a symmetrical 3 bolt pattern measuring 1.190" center to center from bolt hole to bolt hole. The male register on the back is measuring .873". Match those measurements up to those and see if it matches. If it does we have them in stock and ready to ship. Thank you.
If the part ultimately fits, they will most certainly have my business.
Anyway, back to this little adapter. It bolts to the outside of the cam sprocket. I can't envision the step on the cam or the thrust plate (on the in-side of the cam sprocket) interfering with it's installation, if the bolt pattern is in fact identical.
The next issue to verify would be the register hole in the center of the cam sprocket. I wonder if they are a standardized diameter throughout all sprocket manufacturers and if they're standardized within the different GM V8 families.
Again Kip, thank you for your input thus far and any you offer in the future. I get that I'm somewhat blinded by wanting to hear what I want to hear, but I'm equally happy to know, with certainty, that the adapter wont fit too. Or, even that it might. It's only a $25 part, if there's any ray of hope, I'll just order it and see what happens.
If anyone has an LS cam sprocket (or cam) and a digital caliper handy, I'd really appreciate it if you would/could help me out a little and measure center to center, bolt hole to bolt hole to get the spacing. The random act of internet gearhead kindness will not go unappreciated
OK here it is. The cam on the left is a LS1 step nose as we call it. It has a 1.158 bolt circle. The cam on the right is a Small Block Chevy. It just like the BBC it has a 1.360 bolt hole circle.
I used the above picture and measured the spacing.
Hilarious!
Originally Posted by Kip Fabre
OK here it is. The cam on the left is a LS1 step nose as we call it. It has a 1.158 bolt circle. The cam on the right is a Small Block Chevy. It just like the BBC it has a 1.360 bolt hole circle.
Kip, thanks for the great reply. The photo definitely iced the cake. Hard to see right off, but a quick measure of the picture shows a definite difference between the two, which is a big help. Seeing it, somewhat firsthand, settles my curiosity much more than just hearing/reading it.
You're awesome. Thanks for being one of the more helpful guys out there.
Time for more research, maybe a new thread, and figure out how to do this.
09-19-2014, 07:40 PM
