ProtouringFBody's subframe connectors for 1st and 2nd gen Firebirds

Hi all. My suspension and all chassis components are completely refurbished.  All springs, bushings, front end pieces, sway bars, shocks, spring mounting hardware etc are new or restored. I just bought a pair of these and plan on installing them this winter.  I am going to bolt them in for now because my Energy Suspension poly body bushings are new as of last winter and I do not want to replace them yet.  I will be getting solid body mounts soon and will weld the connectors to the rear frame rails then.  I have heard nothing but good comments about these connectors from other Firebird enthusiasts on other boards and was wondering it any body has them on their car?  For $197 with mounting hardware and delivered to my door, I had to get these.  I have a limited amount of cash flow for upgrades this year and I just can't wait to see how even better my suspension is going to feel.  Right now the car is fun to drive and is very responsive.
You can check out my build page at AGTA.
http://allgentransams.com/forum/index.php?topic=2327.0
Here is the link to Protouring's site
http://pro-touringf-body.com/  

I actually used them in many Camaros and Firebirds of the younger generation.

The best thing you can do is have the car at ride hieght. Have the weight of your Firebird on it wheels. This way when you install them the car is at it's ride height. Check the bolts regulary to make sure the bolts don't back off. I've always tack welded the bolt in ones for that reason I think they flex a little more then the weld ins. If you can tack weld them. Good Luck..    

Yes, I can easily tack weld them.  And thank you much.   that is a very good idea.  when you installed them in your cars, did you have a noticable difference in handling?  I will be using home made crush sleeves inside the end of the sub frame to prevent disortion and to allow me to get a good amount of torque on them.  I probably will use some Locktight also.  My question is, by tack welding them, will I be putting added stress onto the poly body mounts.  I do not want any disortion of the subframe body mounting holes to occur.  That why I was going to wait until I get solid mounts to weld them in. I could weld in the crush sleeves to add more strength I guess.  

I don't have these, or even a subframe car. Looked at your thread but didn't find what power level you have. But I would recommend installing the connectors with just bolts at first. If you torque them well and after a time, you can see where movement has occurred (maybe fog the bolt heads with spray paint after torquing), then weld them with a few short beads. If no movement, go ahead and keep driving. If you plan a body bushing swap, just bolt them on until then. In my opinion, you shouldn't need something as drastic as sleeves until you're back-halved, pulling wheelies and running slicks in minitubs and a rollbar. Just some thoughts from a body man!  

Correction- duh, I found the power level described on your thread. My advice stands. Super-sanitary car, nice!    

Body to frame bushings are made to isolate engine vibration and front sub-frame movement (road vibration and flex) from your car.  Poly mounts are already harder than the rubber factory mounts and in my opinion Solid Mounts are probably too harsh for the street. Adding the the rails will help stiffen the body some more but I don't think you will improve the handling much more by adding them.  I just looked at your link and 375 hp doesn't really require sub-frame connectors but they will keep torque form twisting the body with those 4.11 gears. (BTW, as you know,  these reduce your top end and make the motor work harder on the street and 3.55s or even 3.73s might make you happier)

Matt's, advice is very sound and you can never go wrong following it.  I would normally recommend welding the front of the connectors to the front sub-frame and the back. I understand why you may not want to do that right off but that will be strongest. I would also recommend, depending on the design of the connectors, cutting  some material from the leading edges of the connectors (sides and bottoms) so the weld ends up making a jog, sort of "Z" like . This will make that weld stronger than a straight line weld. Cutting a 1 x 1 notch in them will also accomplish the same thing. The more welding area the stronger the bond is.

You didn't say in this post what you are doing with the car. Just street, autocross, racing at track events, or running from the law with 500 gallon tank of Moonshine on board. What you do next depends on what your goal is. You have done the main things to improve the handling but going further is dependent on that goal and your wallet.  Reducing the unsprung weight with lighter wheels and brakes, and better wider rubber will help improve the handling more. I do love a car that handles! There are a lot of fast cars out there that will scare the P out of you when they try to turn and handling makes the difference between fast and very vast - not to mention a much safer car.  Keep us posted on the progress - you have done a nice job on the car so far.  

I want the car to be streetable with an occasional run at the strip.  Nothing crazy. I am quite happy right now with the way the car handles.  It corners quite nicely for a street car.  My ultimate goal is to build my 400 pontiac motor and install it into my 76. I want the car to be able to handle 500 hp just in case my plans change.  I see more chassis strength as very positive and is why i decided to get the sfcs.  
I appeciate your advice and have already thought of going to 3:73 to make the car more highway friendly.  When i welded in my donor rear frame rail ends, I actually narrowed another piece of frame rail and welded it inside the repaired rail inorder to add strength and give me more surface area to weld.  I completely agree with you about cutting a dibet into the sub frame connector to give more weldable surface area.  
Right now, on the back roads, the car feels very nimble and manuverale to me.  It is a joy to drive and turns lots of heads.  I will bolt the sfcs in for now and monitor them closely.  If I see any movement, then I will weld them in as Mike suggested.  I am very anal about my car and am always recheking everything.  

You've done a lot to make your car turn and you might want to check out "Article 4 - Competition on the Cheap" http://forums.highperformancepontiac.com/70/8566296/the-general-discussion/artical-4-competition-on-the-cheap/index.html

It is about Autocross and it is a cheap and legal way to test your car. Also Supercevey Magazine has an article you may be interested in (just cross out Chevy and pencil in Pontiac)

The 2011 Super Chevy/Nitto Tire Suspension and Handling Challenge showed off some trick new hardware, and cool real-world bolt-ons to make your Bow Tie a road-handling terror.
http://www.superchevy.com/toc/thismonth/index.html#ixzz1gB6wFHyh

Finally HPP may also have an Article you will find useful http://www.highperformancepontiac.com/tech/hppp_1005_full_race_car_suspension/wheel_alignment_specifications.html  

Thanks for the links.  those articles were very interesting.  

I recieved the Gen III connectors from Protouring Fbody and they look awesome.  I took some pictures of them still in the wrapper.  I will bolt them in to start using propper torque and monitor them for any movement as mentioned above.