Hot Rod Forum banner

1 - 13 of 13 Posts

·
"May the Schwartz be with you"
Joined
·
1,053 Posts
Discussion Starter · #1 ·
327 Chevy, .030 over, 12.73:1, 292/302, Lift .488/.510, Single 4 tunnel ram.

1985 Firebird, 3000 converter, 4.11 gears.

Do you think a 700 mech. secondary double pumper is too small?

How about if I dropped compression to 10.5:1?
 

·
"May the Schwartz be with you"
Joined
·
1,053 Posts
Discussion Starter · #3 ·
She is built to withstand 8,000, but don't really want to go farther than 7,000-7,500.

I have been having trouble tuning this thing, and was thinking maybe the 700 was too small eben though it figures out ok in the calcs.
 

·
Premium Member
Joined
·
8,453 Posts
I built my own tunnel ram about 1966 or so. May have been the first one ever built?!? Anyway, it had NO bottom end which makes total sense 'cause the velocity signal is totally killed in the shoe-box section. I'm afraid you are stuck with great +3000 potential a the expense of way less than acceptable bottom end performance. Those manifolds are intended solely for top end operation with NO bottom end. So is the double pumper. Only suggestions I can make are 1) consider getting a vacuum secondary carb and/or significantly reduce the plenum volume of the manifold with Devcon Liquid Steel.
 

·
"May the Schwartz be with you"
Joined
·
1,053 Posts
Discussion Starter · #7 ·
[email][email protected][/email] said:
I built my own tunnel ram about 1966 or so. May have been the first one ever built?!? Anyway, it had NO bottom end which makes total sense 'cause the velocity signal is totally killed in the shoe-box section. I'm afraid you are stuck with great +3000 potential a the expense of way less than acceptable bottom end performance. Those manifolds are intended solely for top end operation with NO bottom end. So is the double pumper. Only suggestions I can make are 1) consider getting a vacuum secondary carb and/or significantly reduce the plenum volume of the manifold with Devcon Liquid Steel.
I am not interested in bottom end, I just want the thing to scream (there is sanity to my madness).

I can raise my idle to around 1500 or so, which takes care of the instant fouling of my plugs at idle.

The question is, do you all think the 700 is the right size carburetor for my "current" set-up?
 

·
Registered
Joined
·
1,072 Posts
If all you care about is top end...sure, the 700 should work. However, I dont think youll ever get that combo to run great across the board.
 

·
"May the Schwartz be with you"
Joined
·
1,053 Posts
Discussion Starter · #9 ·
stepside454 said:
If all you care about is top end...sure, the 700 should work. However, I dont think youll ever get that combo to run great across the board.
Thanks, and yes, I don't care about anything but WOT. The car is not street legal.

I was just wondering if maybe I should go to a bigger carb.
 

·
"May the Schwartz be with you"
Joined
·
1,053 Posts
Discussion Starter · #11 ·
Just out of curiosity, what kind of times do you think I could get out of this setup (1/4).

The car is gutted and weighs about 2900 with me in it.

9" Ford 4 link with 17" MT's (DOT)
 

·
Registered
Joined
·
1,072 Posts
dont really know enough about the entire package, but Id say mid 11s with proper gearing

just hard to say without more info, dont know what heads you have, if that cam is hyd., solid, hyd. roller, roller, duration @ .050, lobe seperation, what tranny, tire diameter et. etc.
 

·
"May the Schwartz be with you"
Joined
·
1,053 Posts
Discussion Starter · #13 ·
stepside454 said:
dont really know enough about the entire package, but Id say mid 11s with proper gearing

just hard to say without more info, dont know what heads you have, if that cam is hyd., solid, hyd. roller, roller, duration @ .050, lobe seperation, what tranny, tire diameter et. etc.
I understand what you're saying. I know what times the engine ran in my S-10, so I have an idea of what to expect out of this car.

I had just been pondering the carb size.

If the track over here ever opens for 1/4's again, I'll post slips. They cut it down to 1/8's because the end of the track was in poor shape.

Thanks for the replies.
 
1 - 13 of 13 Posts
Top