Trick Flow Stage 1 in a Cobra?

You should be able to use stock length pushrods if the cam was the only change you made. As far as using shims, that depends on whether or not any further adjustment was necessary, like if you were going from stamped steel rockers on a GT, to roller rockers. The Cobra already has rollers in a 1.7:1 ratio, so the TFS1 cam would necessitate checking PTV clearance if retaining the factory rockers.

I didn't have to change my pushrods, they are the original ones... but i did my cam on a budget -

I did take off the 1.7's before i put in the TFS 1 because i had a bigger cam in there, and i just never put them back on...

it was a straight bolt in for me, the only other thing i replaced was the timing chain.

When I swapped in my TFS1 cam the first time I also added my gt40 heads that were then un-ported. You should not need to use shims or change the PR...its good to double check though to be sure. I think it would be better to move to the 1.6's like your planning (guessing this from what you posted).

Personaly, I would rather get the lift from the cam not the extra stress on your valvetrain by the diff. rocker ratio. I was going to go with 1.7s and to me the biggest thing was the fact they are roller tipped and the stock 1.6's are not.

I asked this question awhile ago on another forum and got some info from Jay Allen and Ed Curtis on the matter. The 1.7 over 1.6 will get the valve action to speed up, gets the valve off the seat faster and get some better mid lift flow if used with the proper head to take advantage of this (a head that flows better in mid lift anyway IIRC).

I think most people who have ran both roller 1.6's and roller 1.7's on avg. will say little to no gain from the 1.7's.

That and with the stock gt40 heads the tfs1 cam is already as big as you would want really with the 1.6 numbers for what the heads like in lift and dur. as in on the high side of the lift, and could maybe use 1-2 more in dur. diff. IIRC from what research I found on what they like. So really with the 1.7's on that cam will put the cam at just more lift than needed.

With my ported gt40's and the TFS1 cam, I was (kind of another reason, why I asked to begin with) wanting to run the 1.7's and see if it was worth the extra lift...I was going to swap back and see if any gain was there. I am not running the 1.7's. I will run 1.6rr and if I need more lift will change the cam. Jay Allen even said it would prob. be a wash on the setup.

Adding even the TFS1 cam to the stock GT E7 heads is not worth the work. Way to much cam for the stock heads...might sound nice but the stock cam is fairly well matched to the stock E7 heads.

He did mention something about it in a cobra too, they had the cast iron gt40s, but also had a diff cam, so gains would probly minimal in both cases. new Heads and cam at the same time