subframe connectors and stock class Q
 

as some of you know, i'm looking at building a 67 american for stock and as there isn't any (to my knowlege) "bolt in" connectors made.
are weld in's acceptable?
what's legal, what ain't?

Re: subframe connectors and stock class Q
 

In my opinion, the most structurally sound way to install frame connectors is to connect the front and rear subframes with the connectors welded INTO the floor where clearances above and below allow. It basically requires a snug channel where the 2x2 or 2x3 tubing would pass through the floor and would be welded along the length. Some higher floor sections may not need a floor cut. Then an 8 pt. roll bar would include 2 legs from the sides of the main hoop, behind the seats, being welded into the top of those connectors. "Triangulation" is the key to a stiff frame/chassis.

But a simpler way would be to fit a 2x2 below the floor or pushed slightly up into it and welded at all contact points, including the roll bar legs. I believe .083" is a popular thickness but have heard as thin as .065" being used.

Re: subframe connectors and stock class Q
 

Both our Camaro and Nova had weld in frame connectors, never had any questions about them from any tech guys, Henry. (old 1608 from the 80-90's)

Re: subframe connectors and stock class Q
 

Looking at both "2008" rulebooks, I don't have newer ones yet. NHRA calls for a maximum of 2 x 3 x .125. IHRA calls for a maximum 2 x 3 x .120 mild steel. I'll leave it to others more experienced than I to advise you on the minimal allowances.

I agree with the triangulation. My 66 Chevy II bracket car doesn't have this. I intend to rectify that before we return it to the track. Our crate motor Firebird will have alot more thought put into the chassis before we begin construction.

Good luck with your build,

Robert Swartz

Re: subframe connectors and stock class Q
 

Welded is acceptable. You can also use round tube and chromoly is acceptable also.

Re: subframe connectors and stock class Q
 

thanks guys, i wasn't sure if it was legal to run them thru the floor if nessassary
(obviously welded in)...
i've been told that in late 68 americans and all 69's that amc added them in oem.
i know my 69 has 'em but the 67 don't...


2X3 X .125" ok? (nhra book says so) or would you suggest a thinner wall tube?

Re: subframe connectors and stock class Q
 

Sub frame connectors are only legal when used with a roll bar or cage.

Re: subframe connectors and stock class Q
 

i'm ok with that...as i'm figuring on a cage.
need the weight;)

Re: subframe connectors and stock class Q
 

Again, just my opinion, but 2x3 and .125" seems like overkill on strength and weight, not to mention possible clearance issues above and below the floor. Having it welded into/through the floor with the inner roll bar legs should make 2"x2"x.083" plenty strong. Then you can add any extra weight where you want to and where it will do the most good.

Re: subframe connectors and stock class Q
 

??? That's news to me.