I have been Building Holleys since the 70,s, Believe it or not My old Holley performance books show mods than any new one does, I have a running engine stand just for building carb testing, Everyone Comes to me, But getting old now, hard seeing, Love doing them Great video
I got a mystery 750 single pump carb, vacuum secondary mainbody, 4 corner idle and mechanical secondary throttleplate on a 351 cleveland running mid 10s on motor. I can't figure out why it works so good, now you got me thinking that someone mightve put a 850 throttle plate on it.
I have Grumpy Jenkins book. There's a chapter where they modified a 660 center squirter to accept a 850 cfm throttle plate. Claimed it improved drivability in Pro-stock engine.
Any time your matching throttle plate size to venturi size your changing velocity, that will help most conditions and especially with a tunnel ram. This works well with a 4150 style carb, but dominators throttle plate and main body are cast together, so look at your holley dominator spec. book and check out throttle plates to venturi size differences between say a 1050 and 1150 and tell me which will have the best throttle response, I guess I've always loved making naturally aspirated horse power , this is probably not as important with power adders. Bill Jenkins and Bob Glidden were two of the best pro stock racers in their time, much respect. When my kids were growing up they raced go carts and at that time briggs and Stratton flat head engines were being used, they had a class called stock appearing and that fit me like a glove and we won like 3 or 4 champion ships due to carburetor mods and connecting rod length what I'm getting at is certain modifications like changing rod length can help a poor or restricted intake port work better, that was one of the main reasons why the little briggs run so well they thought we were running performance additives. Sorry to get so long winded, any who something to think about. Take care.
I've been looking for a few weeks on info to convert vac secondary to mec and I have not seen anyone with the indepth knowledge or the stones to make a video. Thanx for your experience and your time providing these vids... I SUBSCRIBED immediately. The other insane idea kicking around is to see if I can convert a 750cfm (1 11/16) throttle plate to an 850cfm (1 3/4) plate. As you know, there is not much meat there and the tolerances are quite tight/specific. Always thinking down here in gainesville...matthew
With all the work of machining the casting and linkage and bowls. You still end up with a holley double pumper. I believe you would spend a lot of time and money.
Quick question for you. I have an original Holley 3310-2 that I restored. It has with a worn out original baseplate. I purchased a new 112-9 replacement baseplate made specifically for the first 4 generations on 3310. The transfer slots on the new unit are all the same length and short like the secondary transition slots are on most Holleys. The old base plate and my last two Holley carbs had longer primary transition slots. Could this 112-9 be a defect? All four T-slots measure .01945. Any ideas?
Its hard to say without seeing it, I've set up Holleys with no transfer slots exposed at idle at all, so the idle mixture is controlled by the mixture screws only and the transfer slots operate only above idle. I have seen some machining errors on the transfer slots but rarely.
bill I believe the 830 performs better with annular boosters should make good power and better throttle response , the idle circuit can be leaned out some , I'll try to do a video soon.
I have a 950HP which isn't really 950cfm. Its a 850 base with a 750 main body. Not sure why Holley calls it 950. Do you know where I can send my current main body to have opened up to 950 size? Do you do this?
I've never tryed to resize the venturi area, the only company that i know might, would be blp (Bo laws Performance). I don't know for sure but you would have to replace all four boosters and resize the venturi, might cost more than a new main body. Hope this helps.
added a 850 1 3/4 alcohol baseplate to a 750 quickfuel 750 e85 and not it's so lean i can barely keep it a running. opened up idle screws added jet size. Can lightly pump it to keep it alive. afr meter shows extreemly lean. Carb ran like a dream before but little too small. Any ideas?
I will do a video soon , but when you install an 850 throttle plate on a 750 main body it blocks the idle circuit some rebuild kits come with a special gasket for this modification , check in your rebuild kit if not watch for my next video.
@@holleycarbshowtosadvice40y90 Yes, I had found that i missed that, had to offset drill channels to match also. Is it common in this swap that the slot is running rich? Idle screw i leaned out but off idle and into light cruise is now very rich.
The venturi is 1.600 on the new ultra list # 80805 950 main body , may bolt up with no issues , never tried this combination , but these dimensions are the same as the 950 ultra hp carb. The old 950 body may not be available , but a 750 main body can be used with some blending and idle circuits modifications , venturi is 1.376 same size venturi as the old 950 list # 80496 hp .Hope this helps
Randy,which video shows the modification (850 plate / 750 body ) with the idle passage mods ? I watch your videos over and over to hammer the knowledge into my old hard head.
I'm an old builder to it's hard to make new guys understand u done ah good job wanna watch 850 base on 750 sounds like real good street carb thank an keep it up trannytuck
Well hopefully covid19 didn't take you out because I am still waiting for the 750 holley main body onto the 850 base plate video you claim here to be doing 2 years ago....
I have been Building Holleys since the 70,s, Believe it or not My old Holley performance books show mods than any new one does, I have a running engine stand just for building carb testing, Everyone Comes to me, But getting old now, hard seeing, Love doing them Great video
I know that feeling , I feel like using wd40 on every joint lol, use a flashlight more than ever, I guess that's part of being an old geezer .
I like the Allen Johnson Rod just chilling on the Table!!
Me too.
I got a mystery 750 single pump carb, vacuum secondary mainbody, 4 corner idle and mechanical secondary throttleplate on a 351 cleveland running mid 10s on motor. I can't figure out why it works so good, now you got me thinking that someone mightve put a 850 throttle plate on it.
Yes I would like to see it .
Randy,
Not sure if I missed the 750 to 850 throttle body modification but looking forward to it
Sorry it's taken so long, will do soon.
I have Grumpy Jenkins book. There's a chapter where they modified a 660 center squirter to accept a 850 cfm throttle plate. Claimed it improved drivability in Pro-stock engine.
Any time your matching throttle plate size to venturi size your changing velocity, that will help most conditions and especially with a tunnel ram. This works well with a 4150 style carb, but dominators throttle plate and main body are cast together, so look at your holley dominator spec. book and check out throttle plates to venturi size differences between say a 1050 and 1150 and tell me which will have the best throttle response, I guess I've always loved making naturally aspirated horse power , this is probably not as important with power adders. Bill Jenkins and Bob Glidden were two of the best pro stock racers in their time, much respect. When my kids were growing up they raced go carts and at that time briggs and Stratton flat head engines were being used, they had a class called stock appearing and that fit me like a glove and we won like 3 or 4 champion ships due to carburetor mods and connecting rod length what I'm getting at is certain modifications like changing rod length can help a poor or restricted intake port work better, that was one of the main reasons why the little briggs run so well they thought we were running performance additives. Sorry to get so long winded, any who something to think about. Take care.
This is exactly what I needed !
Thank you sir. I'm doing the 830
Let me know if I can help you. Thanks for watching.
do you have a part number for the catalog. you have
I forgot to add it. P/N L30968
You can also get it for free on the internet. Just search Holley list numbers and you can download it as a PDF.
I've been looking for a few weeks on info to convert vac secondary to mec and I have not seen anyone with the indepth knowledge or the stones to make a video. Thanx for your experience and your time providing these vids... I SUBSCRIBED immediately. The other insane idea kicking around is to see if I can convert a 750cfm (1 11/16) throttle plate to an 850cfm (1 3/4) plate. As you know, there is not much meat there and the tolerances are quite tight/specific. Always thinking down here in gainesville...matthew
With all the work of machining the casting and linkage and bowls. You still end up with a holley double pumper. I believe you would spend a lot of time and money.
I've got a friend that I'm doing a 750 body to a 850 throttle plate , I will show it on a video soon.
@@holleycarbshowtosadvice40y90 wonderful...thanx
I converted a double pumper to a vacuum secondary. Wasn’t hard
Quick question for you. I have an original Holley 3310-2 that I restored. It has with a worn out original baseplate. I purchased a new 112-9 replacement baseplate made specifically for the first 4 generations on 3310. The transfer slots on the new unit are all the same length and short like the secondary transition slots are on most Holleys. The old base plate and my last two Holley carbs had longer primary transition slots. Could this 112-9 be a defect? All four T-slots measure .01945. Any ideas?
Its hard to say without seeing it, I've set up Holleys with no transfer slots exposed at idle at all, so the idle mixture is controlled by the mixture screws only and the transfer slots operate only above idle. I have seen some machining errors on the transfer slots but rarely.
I have an 830 on a 396. Interested to learn more about its strengths and weaknesses. Seems to run ok. Except rich.
bill I believe the 830 performs better with annular boosters should make good power and better throttle response , the idle circuit can be leaned out some , I'll try to do a video soon.
Is it rich at idle or at cruising speed, either way we can lean it down, let me know and I'll do a video .thanks for watching.
I put 750 throttle plate on 600 vac secondary .it's such a great upgrade ..just have to tune idle transfer circuit to make it perfect
Let me know how it turns out, good luck.
I have a 950HP which isn't really 950cfm. Its a 850 base with a 750 main body. Not sure why Holley calls it 950. Do you know where I can send my current main body to have opened up to 950 size? Do you do this?
I've never tryed to resize the venturi area, the only company that i know might, would be blp (Bo laws Performance). I don't know for sure but you would have to replace all four boosters and resize the venturi, might cost more than a new main body. Hope this helps.
@@holleycarbshowtosadvice40y90 Your probably right. Easier to get a new main body.
Doing this today to my 750 main body and 850 throttle plate. Annular booster to
Good combination.
I clicked the link to order catalog but it does not pull it up. Help please
Dwayne don't know about the link , I would call holley.
added a 850 1 3/4 alcohol baseplate to a 750 quickfuel 750 e85 and not it's so lean i can barely keep it a running. opened up idle screws added jet size. Can lightly pump it to keep it alive. afr meter shows extreemly lean. Carb ran like a dream before but little too small. Any ideas?
I will do a video soon , but when you install an 850 throttle plate on a 750 main body it blocks the idle circuit some rebuild kits come with a special gasket for this modification , check in your rebuild kit if not watch for my next video.
@@holleycarbshowtosadvice40y90 Yes, I had found that i missed that, had to offset drill channels to match also. Is it common in this swap that the slot is running rich? Idle screw i leaned out but off idle and into light cruise is now very rich.
Are any mods need to put 950 main body on a 850 base plate? Your video are great.
The venturi is 1.600 on the new ultra list # 80805 950 main body , may bolt up with no issues , never tried this combination , but these dimensions are the same as the 950 ultra hp carb. The old 950 body may not be available , but a 750 main body can be used with some blending and idle circuits modifications , venturi is 1.376 same size venturi as the old 950 list # 80496 hp .Hope this helps
Welp, youve earned my subscription... please make more vids! Keep up the great content
Thanks
Randy,which video shows the modification (850 plate / 750 body ) with the idle passage mods ? I watch your videos over and over to hammer the knowledge into my old hard head.
I dont have a video yet on the 750 body with 850 plates, I'm going to order a billet 850 plates , will do one soon.
current price as of 4/23/2020 is $50.00 + tax for the book with all the specs,
If that book is like mine , you love it , good luck.
Thanks for the information.
Absolutely.
Good stuff 🍻
Thanks brother.
Great tip thank you
Your welcome.
I'm an old builder to it's hard to make new guys understand u done ah good job wanna watch 850 base on 750 sounds like real good street carb thank an keep it up trannytuck
I've got to find an 850 throttle plate, hopefully have a video soon.
good stuff.
Thanks Bob
Well hopefully covid19 didn't take you out because I am still waiting for the 750 holley main body onto the 850 base plate video you claim here to be doing 2 years ago....
I apologize for the long delay , but it can't be helped . Will try to do something soon.