Upgrades for the Big Boat Bash

[71GSX455-4Spd]

I'm finally going to get around to installing the upgrades I have sitting in my garage in preparation for the Big Boat Bash. A TH400 that I just picked up from being rebuilt and a 3.42 9 3/8 rear to put in. A Trishield 9.5" 2700-3000 stall converter will go in front of the trans. I have a set of TA SE Stage 1 heads with a mild clean-up from Greg G (no flow numbers) with an SP1 intake. I have a 413 cam, but I'm really thinking about this unit as I know several people have had power brake issues. I was talking to John Csordas and may try to call Scott Brown, although I don't know what his lead time is. I also have two carbs to choose from- an 800 Qjet done by Jim McGowan or a Prosystems 950HP. I'm hoping the Q-ject comes out on top as it probably has much better street manners. The engine this will be going on was built by Trishield and has forged 10:1 pistons, but I'm not sure how far in the hole they are as the deck was just cleaned up to square it, so I'm sure the actual compression is less, maybe 9:1. I'm running an ignition man distributor with and MSD6a box, but have an MSD Pro Billet distributor that came with the box that's also possible, although I don't think it has a vacuum advance. Finally, a set of TA long tube headers that I plan to go into an X before going into the Dynomax long case mufflers that are on the car. I have a Pontiac big car trans tubular cross member that should clear these headers without an issue. I've been accumulating parts for several years....

Just typing that tells me I have a lot of work to do!!

It's going to be close.....

Oh, this is intended for the '72 Riviera

[Harold Rolls]

Hi Ken. I run a 413 cam on my 69 for a few years, with power brakes, and never had a problem. Good luck.

[71GSX455-4Spd]

Harold, did you have a vacuum reservoir? Or just a tightly sealed engine? No problem with multiple successive stops? I'm curious as I have this cam, Yardley runs really fast in a similiar weight car with this cam, etc.

Thanks for the feedback!

[Harold Rolls]

Harold, did you have a vacuum reservoir? Or just a tightly sealed engine? No problem with multiple successive stops? I'm curious as I have this cam, Yardley runs really fast in a similiar weight car with this cam, etc.

Thanks for the feedback!

Ken. Just straight power brakes. I THINK the vacuum at idle was about 11. Notice I said think. I plain can't remember. Just no brake problems, in town or out.

[69GS400s]

better get busy there Ken ... and when you're done, there's an "aging" but fresh 462", JW th400 + 9.5" converter, 12-bolt with Metco uppers/lowers, and and a GV unit that all needs to be installed in the GSportWagon

... I knew you were good at taking them apart but never imagined you had mad skilz building them too

WoooHooo !! Road Trip

I had a 413 in BigRed for about 5 years, drove about 30-40K on it. Brakes were OK but certainly not great. Tried a can but it didn't noticably help. If you really have a problem you can always run an electric vac. pump setup.

You learn to drive it like you got one good shot at the pedal - usually you have more but ...

If you feel you dont even have that, thats when you pucker up

[71GSX455-4Spd]

Hey, now, let's not get ahead of ourselves- I haven't actually put anything back together yet, it's all talk!

I think I'll end up putting the 413 in, Yardley hasn't killed himself yet with brake issues. Then again, I don't even know how to work the brakes on a moped...

I remember looong ago you suggesting I put dished pistons in this motor as I might want to upgrade someday to something hairier. If you remember, this was supposed to be the "play" motor for the GSX, so I didn't follow your suggestion. The GSX ended up with it's numbers motor and the play motor is sitting in the Riv waiting to get yanked for this upgrade. Wish I had listened. Need to pull it apart, but I'm guessing the pistons are in the hole .030 and I probably don't have enough clearance to cut the heads and intake. Oh well! Not going to pull the shortblock apart.

What's the build on that 462 you have sitting there?

[Yardley]

I'm zero decked with shaved heads and no piston notches. No issues.

[gbsean]

I'm zero decked with shaved heads and no piston notches. No issues.

I will have to agree with above statement...but you do have issues

[Yardley]

Brother, you don't know the half of it.

[d7cook]

may try to call Scott Brown,

I highly recommend SB. I've had real good results with his custom grinds, they cost the same as an off the shelf cam and he usually turns them around in a couple weeks.

[71GSX455-4Spd]

Good to hear on Scott B and his turn around times, but I may end up sticking with what I have! I just talked to JW and he told me my block is zero decked! I thought it was just squared up and made true. He recommends leaving the cam that's in there (288-94h) and spending the money on porting the snot out of the aluminum heads. The 288-94h has a .488 lift with a 288 intake duration and a 294 exhaust duration on a 114 lobe center. The 413 has .500 lift with a 286 intake/296 exhaust on a 113 lobe center. He thinks there's little to be gained with the 413, so this project may have just become a bit easier (no motor pull). Jim thinks the current cam will give plenty of air for a higher level of porting without sacrificing little things like brakes.

I have a call into Greg Gessler....