Simple fiberglass bolt on scoop tech

[CDMBill]

Due to an excess of induction height on the new engine I've had to cut a hole in my daily driver cowl hood. This was not my ideal plan but there simply aren't a lot of choices for my odd ball car. (71 Mustang) I don't like scoop on cowl set-ups either so please save the insults, I have already beat y self up over this one and there wasn't a better air cleaner option that was remotely easy to build or cheap.

I will still run a light weight pin on hood for Drag Week but for most f the rest of the year I like using regular hood hinges etc. BTW the fiberglass "heavy duty' hood weighs 74# plus the 203's for the hinges versus the ugly but light 25# pin on set-up.

The question? After having to seriously carve on the replica Boss 429 scoop to get to conform to the existing cowl set up I need to re-attach four of the eight mounting studs. What is the best process to use? The scoop as it came form Branda had eight 1/4 20 studs attcahed with waht looks to be rubber cement surrounded by purple resin. I was thinking of using solar curing fiberglass repair stuff I have for my surfboard which works well on that application.

Any better ideas? I am a complete noob when it comes to fiberglass wok on automotive applications.

[CDMBill]

Some pictures for explanation. New added scopp mounted to hood.



underside of new scoop with carved out stud location shown. Also see ugly ass filter sticking through new cut hole.



Better view of funky hole in hood.



Junk under hood and no I really don't want to compromise the isolator pan as it covers all the linkage, N2O plumbing and provides a semi decent smoothed air inlet to the throttle bodies. Yes it could be better but it fits, sorta.



Even uglier bastard hood set up form DW 2011.



If I have time/money I may build a flat style hood with big ass cowl for DW. I like cowl hoods for driving events due to rain.

[mlcraven]

Full disclosure, the only true fiberglass work I've ever done has been on boats.

It's not a better idea, but might be worth talking to the folks at Branda in advance...if for no other reason than to understand why they mount the fasteners the way they do. The rubber cement has me wondering -- perhaps to limit the potential for cracking when customers over-tighten? Otherwise, see no reason why what you're proposing shouldn't work just fine.

[milner351]

putting some o-rings or rubber washers from the hardware under washers, then nylock 1/4-20 nuts should be good - you need to allow some flex and allow a bit of vibration resistance. Remember to keep away from the polyester "stinky" resin at most parts stores - it's very brittle and really not good for much of anything that moves.

You may feel it's hackery Bill - but it looks pretty good from here!

[SuperBuickGuy]

when one scoop isn't good enough - lol

okay, seriously though - are you going to paint it the same color as the car or leave it black? if you're going to paint, then don't mount it in any way it can move because the paint will crack. In fact, I ignored VFN's advice on my scoop and won't do that again - I fastened then bondo'd the hood scoop down on my Skylark - and it promptly cracked - what I should have done was follow their advice of actually grinding the metal with 80 grit (underside) then bonding the scoop to the hood with fiberglass resin and clothe.
If you leave it black, then no worries, screw it down evenly and forget it.

[CDMBill]

The Branda scoop is still in the black gel coat as it arrived. The orginal plan was to paint it the same color as the car but the contrasting black is beginning to grow on me.

I have some different approaches here and I appreciate the replies. As noted I'm in new territory as I never worried about previous bolt on situations which date to the 70's in my personal experience.



Check out JC Smoketrain here with his 67 back in '74.

[CaminoKid]

I put a functioning scoop on my youngest sons 67 mustang and it cracked the first time.Second time we wet set it in fiberglass and resin,screwed it down with counter sunk screws and glassed over that entire edge.problem solved.
The vibration of three inch pipes and a 331 stroker with 14 to 1 compression was to much for the first scoop.

[Bamfster]

I bounced this off my friend that is a body tech. He suggested knocking all of the studs off and using a panel adhesive to bond the scoop and finish it off with some stranded body filler. It will be 1000 X's stronger than the "old tech" fiberglass way. OEM's have been using adhesives for quite a while to hang panels, in fact GM uses the stuff to hang the bed sides on their trucks.

As far a replacing the studs, he kinda thought that what you think is rubber cement is actually some type of epoxy. If you can find out for sure what it is, it would be best to replicate that. Short of that, and him not being able to hold it in his hands and look at it, he suggested taking it to a auto body supply house and letting the counter guys take a SWAG at it.

[william smith6161]

sounds good to me

[CDMBill]

I bounced this off my friend that is a body tech. He suggested knocking all of the studs off and using a panel adhesive to bond the scoop and finish it off with some stranded body filler. It will be 1000 X's stronger than the "old tech" fiberglass way. OEM's have been using adhesives for quite a while to hang panels, in fact GM uses the stuff to hang the bed sides on their trucks.

As far a replacing the studs, he kinda thought that what you think is rubber cement is actually some type of epoxy. If you can find out for sure what it is, it would be best to replicate that. Short of that, and him not being able to hold it in his hands and look at it, he suggested taking it to a auto body supply house and letting the counter guys take a SWAG at it.

I'm hoping to avoid the rubber cement part of the equation as once the resin glop was ground down a bit the rubber cement was all that was left on .25" of threads. I really like the panel adhesive idea and I'll admit I'm trying to cheap out for a bit on the full on paint and fiberglass bonding which I know is needed to do this right. Ignoring the already compromised esthetics, botching it up further with my amatuerish body and paint work is worse.

The hood is so heavy and stiff that cracking is a bit less of a concern at the moment. The hood itself weighs 75# which is why I bought the cheapo pin on which only weighs 25# plus the 5# scoop. It also lets me remove 20# in hinges and springs and another 8# for the latch mechanism and bracket. 70# off the nose of this pig is big deal for the racing side of the equation.

The funky pin on one is back on it for Bakersfiled this weekend then it'll be back to finishing the street set up.

[Scott Liggett]

I like this guy's idea.

[BBR]

I like the flat hood w/ cowl 1000 times better.

[CDMBill]

That is the idea! That guy has done a nice job on the stance and the straight forward cowl. Nice to see it in a picture. Is this someone you know James/ I'd live to find out where he got the hood and scoop. A cowl set up has to be taller and start earlier on mine due to the tunnel ram dual TB setup but that's a nice clean approach. I tried to figure that out with the repro Mach 1 hood but the NACA scoops are too far back for a nice sloped cowl like that to fit. I drove up to Unlimted Products near Apple Valley three times in three days (150 mile round trip) trying to get that figured out at the last minute last year.

My car came with the body color trim and bumper but I'm kinda diggin' on the chrome offset against the primer grey.

[BBR]

I agree, that car has a nice stance. I just used google and found that pic. If it were me, I'd start with a flat fiberglass hood from darkhorse or someone and have a bodyshop (boat shop maybe?) glass in a harwood universal cowl.

[Bob Holmes]

Man, I agree, that car looks great.

I think when you do the "hot rod" primer, or flat, the bits of shiny are necessary to set it off.