old school tunnel ram and carbs question

[Salvatore]

Dave, You sound right on. Small Carbs that run 85-90% efficient is much better than big carbs running 60% efficient. Need steep gears and heavy flywheel. My friend Pete used to run a 50lb. wheel with a 6.17 ring and pinnion and a 3.00 first gear in a Nash 5 speed. Car was 280 cubes in a 57 2 door wagon that weighed about 3400lbs. 10.82 @ about 130mph back in 1979. Carbs were inline (660) center squirters with an Engle roller cam. (G/MP)

[JoeG]

engine whitetop--Are you running a straight linkage ie.-1 to 1 ratio or progressive setting on your linkage

[whitetop]

I'm running Weiand straight linkage. Not progressive. I think the part number is 4011 or something like that. Both of my carbs come out to 780 cfm which even on a little 289 is more than is recommended but it is the smallest 4150 carb available from Holley.
BTW Running a Crane cam, very mild. But it produces a ton of vacuum and torque which is needed to run a tr on the street.

[musclcar]

your getting me confused now you mention a 4150 carb "double pumper" then you mention a 4160 "vacum secondary.so what is better for my tunnel ram double pumpers or vacum secondary carbs. i don't think there is room on a TR1-X for 2 inline double pumper carbs.the vacum secondary carbs i've got now the bowls are seperated by less then a 1/2 inch between the front and rear carbs. so your saying a 600 cfm vacum secondary carb will be to much and i should go down to a 450cfm vacum secondary carb for better results.i bought 2 matched 600 cfm vac sec. carbs off of ebay for a good price and all they need is a rebuild. the camshaft that's in my motor right now is the GM #140 solid lifer cam and my compression is 11.5:1 and my rear gear is 3.73.

[Salvatore]

I don't think 2-600's are too big. The cam sounds appropriate. Need some good gears. JMO Sam

[BBIGG BLOCK 396]

Correct me if I am wrong,but I always heard that vacuum secondary carbs did not work on tunnel ram setups because the tunnel ram decreases the vacuum on the engine!I remember a long time ago that my brother had to change out his carbs to non vacuum secondaries in order to get it to run correctly.

Bobby Dodson

[whitetop]

[ QUOTE ]
Correct me if I am wrong,but I always heard that vacuum secondary carbs did not work on tunnel ram setups because the tunnel ram decreases the vacuum on the engine!I remember a long time ago that my brother had to change out his carbs to non vacuum secondaries in order to get it to run correctly.

[/ QUOTE ]

Was he possibly running too wild of a cam that produced no or little vacuum. Car Craft in the late '70's had a very extensive TR setup article for the street. All the pros who they interviewed recommended a VS carb. I think the jist of the article was for the street a VS only used as much gas as needed while a mechanical secondary gives you the gas whether you wanted it or not. I've also talked with many people who had cars like the Camaro posted above and asked them and it always came back to VS were best and that is what runs best on my car.

You have to remember we are talking street cars here with driveability as the goal. More show than go so to speak. Not a street/racecar. I was more concerned about my car restarting at a cruise and not popping/spitting etc. I am not concerned about the power.

[JoeG]

Motion had set up a 454 ZLX tr /(2)600cfm--513rear/hone---
Sam your right with the steeper gears with 1200cfm---But ....as Whitetop pointed out the smaller carbs just make life easier on the street--you could spend more time cruisin an less time tuning---JMHOX2----

VAC/MEC SEC---Would depend on cam/vac venturi size on carbs etc as whitetop pointed out and tr design--Whitetop seems to have a winning combo and you go with what works with your mods---

[JoeG]

Here's a photo of an edelbrock tr/(2) 600cfm carbs-str. linkage----From that Motion car---maybe this will help--Just some info

[whitetop]

Chuck
The 600 vac sec carbs maybe alright for your application because you have 50+ more cubes than mine. I would try them and if they don't tune out right go with the 450's. A friend of mine who built a streetrod with a 350 TR had two 600's like your but later put on my 450's and liked them better. Of course his engine was no where near as radical as yours. I think his had 9 1/2:1 Compression. The 450's are not vac secondary but the motor seemed to like the smaller cfm.

Like Sam said you need to increase your gear ratio in the rear. You may have a bog/hesitation when leaving. I can't over emphasize enough if you want to run one of these on the street you need as much vacuum and torque as you can put into the combination. You will not beleive how much torque you will loose from running a TR. Remember these were designed for the strip with cars leaving at 6-8K rpm. My friend who has the street rod only has something like 3;73(?) also but he is running a 5 speed and had a very low gear placed into it for first.