Maybe he means a video?......Engine data results are posted on post #60 of this thread.

 

BTW.....What size is your cowl hood....it looks like a Glasstek 5".....how tall is it?

 

Thanks, no picture for me, says something about photo bucket, maybe some one could repost it?

 

 

Download this link on Firefox browser, it will allow you to see all Photobucket pics.

https://addons.mozilla.org/en-US/fir...=1505219095970

 

Here ya go........

 

Thanks for reposing it and the link! Hopefully others are aware of this. I recently created a thread of my experience hand porting the top end of a 92 ZR1 posting many pics via Photobucket. They pissed off a lot of people when they changed to pay per view. I was not happy to see all my pics vanish.

My cowl is about 5.25" at the highest point. I forget where I got it. It has been many years. Fit like crap. I had to make it fit. It was too narrow and too short. The hood hold-open latch bosses were in the wrong place...... I could write a book on that experience. Most of my mechanical knowledge over the years has been gained by having to make "direct fit" bolt on parts actually fit.

BTW- 5" is what you will need if you ever want to run high rise intakes and spacers. I am currently running the Titan race single plane intake with a 1.5" spacer and non-drop base air cleaner. My filter is K&N 2"x14"dia. I used to run a dual plane airgap with a 2" spacer. I may try the dual plane titan spider with this new engine config to see where the power goes.

It was a tough decision going with the 5" because of its size bit I am glad I did. One of the best upgrades I ever did. Gave me all the room I needed to play over the past 18 years.

 

Thanks for the response. Judging from your pic, the cowl looked around 5" high. I'm considering getting one for clearance. I compromised on the intake (Motown) so it would fit under my hood. A better intake, ported Super Vic II or Holley Dorton Strip Dominator would up my power with my 440" cubes. Glasstek does custom work, so I'm thinking a 5" L-88 style hood.

Using Firefox browser with hotfix add-on you can see all the Photobucket pics. Then, if you open the pic on the Photobucket website, you can copy it to your computer and repost it.

 

I notice you run 4.10 rear gear. How did you do that?

 

Had Strange 4.11 gears for C3 Corvettes installed. These have the thick ring gear that fits in the 3 series carrier.

This........

https://www.strangeengineering.net/p...ar-thick.html/

 

Did you need to clearance the case for the 4.11? When I rebuild mine about 12 years ago, there were reasons why 4.10s were not available. I went with the 3.73. Not sure if is worth going to the 4.11 but it would help the bottom end some now that power band has shifted upward. I also discovered that somewhere in a previous life the car had the rear diff swapped out for a later model unit. If I recall from the numbers it was late 70s. I discovered this when ordering a new leaf spring. They are wider on the 72. Not sure offhand what year they swapped to the narrower spring. I hear the later model design was better. I don't know if this is true. I beefed it up buy over-boring the cap bolt holes and re-tapping for larger bolts and installing higher strength billet caps. I de-burred and polished the Eaton carrier as well.

 

Thanks

 

This build being as close as mine.. and my last Dyno was at 535hp at the rear wheels...
you lost what, 135hp... That puts me at 670hp:-)
Makes sense though... I have a little smaller cam and smaller heads.. 220 competition ported..

I have 0 issues idling down the street at 900 rpm... power starts at 2000 rpm... good to 7000..

 

The installer did not have to clearance the case on mine. The ring gear is sized to fit in the stock 3 series carrier. I believe the diffs are the same from '63-'79. Later ones slightly different (someone could chime in with more info). '78-'82 leaf springs changed (I believe).

I noticed a big difference with 4.11's, but I have a TH400 auto trans.

 

Hello Paul-
I was hoping you would chime in.... after all it was your build that inspired me to pull the trigger on this project. Tomorrow I am going to run it again but this time with the original 950 cfm carb and take her up to 6800 rpm and see what happens.


Awesome house BTW....

 

Excited for you!!!:-) :cheer s:

 

Hmmm, maybe I will look into it. Running out of projects, need something to take apart. I was thinking about going with a light weight fly wheel. I installed a 20lb unit with a dual disc RAM clutch on my 95 ZR1. I absolutely love it! The only down side is noisy transmission and some chatter when I put it into first gear from a stop. I love the fast spin up and instant throttle response. I also put 4.10 on that as well. I just don't know if it will feel the same on a carburetor car.

 

When your done playing with that dyno, send it to my house!

 

New numbers with the 950 carb:

Max rwhp: 572
Max rwtq: 513

I had two other runs both were at 562 hp and 508 tq.
Not sure where that extra 10hp came from, perhaps the fans were not running? We were having some issues with the throttle cable as well but I don't think that is it. I think that had we run the 830 out to 7000, there would have been more HP in it so the actual difference between the two really is almost negligible in my opinion.

I also burnt up my MAP sensor so I used a gauge instead. Not as accurate as a analog signal but it did show that the vacuum dropped to essentially zero during the runs. My fuel pressure also remained steady which is interesting given it is a Holley high volume mech pump run with the stock fuel line.

I was running a little rich during the runs in low to mid 12s. I probably should be in high 12s. I will probably re-jet and do a little machine work on my throttle linkage plate to put to bed this throttle plate travel issue. I have tried everything even removing and bending the pedal arm. It is close but you need to mash it to the floor...I would like a little extra leeway.

Couple of questions:
Is the 950cfm too big, just right or not big enough? Many during my build were saying 1000 cfm Ultra or Dominator would be the way to go.
Should I plug the secondary PV and jet up or keep it. My current secondary jet size is 88 with 79 in the primaries.

It was recommended initially that I try a 1000 cfm Holley Ultra or Dominator.

 

Going back to dyno with new carb from Pro-Systems. Appears to be basically the same carb I had before without the choke tower. 4150 main body with same baseplate and venturi diameters. They set it up quite a bit differently but work quite well out of the box. The only issue I am now having is this carb has a lean spike at low load part throttle.

What surprised me is that this carb also came with all 4 throttle blades drilled. Because of part throttle tuning issues on my old carb I filled all 4 holes. I believe this is what cause the rich condition spike at part throttle I have with that carb. What I learned from all this is certain cams with high lift and over lap apparently need more air and to run at a higher idle than what is typical. There are also reversion concerns into the intake with high overlap cams at lower idle speeds. In order to achieve this holes are drilled into the throttle plates to allow more air. If you don't do this the blades will have to be opened to far into the transfer slot which will cause an overly rich condition at off idle transitions. The only way to correct is to install smaller IFRs. I did this on my older carb (the one that had all the holes filled). It work OK but still wasn't where I thought it should be. I think in retrospect what I should have done is open up two of the holes. My guess is that would have correct the rich condition without having to do much with the IFR. All that said, I filled just two of the holes on the new carb and my guess is that should fix the overly lean condition I am seeing with that carb. I don't expect. My idle is around 12-1300 rpm.

Anyway...not expecting much gain with the new carb. Going this Thursday.