carb selection for yearone CT350PC1 Engine
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 22
Likes: 0
carb selection for yearone CT350PC1 Engine
hi,
i want to upgrade my carb.
i was thinking about a bary grant, but i dont know which one i should use.
i ask the tech support from BG and they recommend the 750 Speed Demon with annular boosters ( pn 1402020) .
but after a look at the BG carb selection guide it seems to big.
at second i asked yearone and they recommend the h80770 street avenger.
which one is the best choice ?
what do you think ?
i want to upgrade my carb.
i was thinking about a bary grant, but i dont know which one i should use.
i ask the tech support from BG and they recommend the 750 Speed Demon with annular boosters ( pn 1402020) .
but after a look at the BG carb selection guide it seems to big.
at second i asked yearone and they recommend the h80770 street avenger.
which one is the best choice ?
what do you think ?
Advanced
Joined: Jun 2006
Posts: 65
Likes: 0
From: SHADY SPRING WV
I have the same engine and they also told me a 750 double pumper. I tried the Holley double pumper and couldn't get it to run right. I tried a 670 street avenger and it ran good but not great. I didn't like the vacuum secondaries. Finally I went to the 650 speed demon and it runs great. No off idle hesitation. I did have to lean it out a little other than that it was good out of the box. Runs strong up to 6000 rpm and I never go beyond that. It does seem to have more left. I know they dyno those engines with a 750 but that is to get top end hp.
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 22
Likes: 0
at the moment im using the 670 avenger too. out of the box it stumbled a little bit, so i rejetted it to 68 pri. - 73 sec. it feels a little better, but i think the engine dont have the power it should have.
which 650 speed demmon you put on ??
where did you set your timing ? ( initial - total )
are you using vac. advance ? ( ported or manifold )
how much vac. advance you add. ?
which 650 speed demmon you put on ??
where did you set your timing ? ( initial - total )
are you using vac. advance ? ( ported or manifold )
how much vac. advance you add. ?
Racer
Joined: Dec 2003
Posts: 399
Likes: 0
From: Haslet,Texas
I have the same engine, but with forged pistons. Since I plan on using the car for street/strip, I went with a 750 double pumper. I haven't started any tuning, so I can't offer much advice on the carb setup yet. My engine dyno'd at 416hp and 455 ft lb tq with the 750 double pumper. What kind of exhaust are you running?
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 22
Likes: 0
@ 73'vette
this is one thing where i loose some power for sure.
at the moment i use some cc90 sanderson blockhugger headers into a short 2 1/2" pipe into a sidepipe.
i know its not the best way to create power but i have to use the short headers because my exhaust is to close to the frame.
if i would use some long headers i have to install the pipe under the frame.
while driving they sometimes would hit the floor and will be damaged.
there is not enough room to go this way.
i thought about to order some hedman headers ( 68500 ) on summit and try to build a better exhaust pipe.
i tryed to put a pic in but i dont know how to do it.
this is one thing where i loose some power for sure.
at the moment i use some cc90 sanderson blockhugger headers into a short 2 1/2" pipe into a sidepipe.
i know its not the best way to create power but i have to use the short headers because my exhaust is to close to the frame.
if i would use some long headers i have to install the pipe under the frame.
while driving they sometimes would hit the floor and will be damaged.
there is not enough room to go this way.
i thought about to order some hedman headers ( 68500 ) on summit and try to build a better exhaust pipe.
i tryed to put a pic in but i dont know how to do it.
Racer
Joined: Dec 2003
Posts: 399
Likes: 0
From: Haslet,Texas
I removed my "fake" (4 into 1) side pipe setup in favor of a true hooker-style side pipe setup. To further decrease horsepower loss, I am in the process of ripping out the glass packs in the side tubes to install a set of STS baffles. You are correct in considering a better exhaust setup to free up some more ponies. Once I get the exhaust completed and do some tuning, I plan on seeing what it can do at the drag strip. Do you remember your dyno sheet numbers?
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 22
Likes: 0
my dyno sheet shows the maximum of torque from 432,2 @ 3700U/min and max. HP from 412,3 @ 5900 U/min.
how should a good exhaust pipe look like?
whereat the focus i like on torque @ lower rpm.
very interessting for my is the timing.
in germany you can get 91 - 95 - 98 octane.
the engine was dynod with 93 octane, with a total timing of @ 32 degrees.
i dont know if it make a big difference ?
how should a good exhaust pipe look like?
whereat the focus i like on torque @ lower rpm.
very interessting for my is the timing.
in germany you can get 91 - 95 - 98 octane.
the engine was dynod with 93 octane, with a total timing of @ 32 degrees.
i dont know if it make a big difference ?
Racer
Joined: Dec 2003
Posts: 399
Likes: 0
From: Haslet,Texas
Your engine dyno'd similar to mine. Mine was dyno'd with 35 degrees timing, so you could try adding in some more timing. I finally got my STS baffles installed, and I'm impressed. They sound great! 
I'm very anxious for a test and tune night at the local track.
I'm very anxious for a test and tune night at the local track.
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Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
How many horses, tranny, torque converter? I have a 400hp 350 SBC and tried Edelbrock, Holley and eventually installed a 750 Speed Demon. Plenty of torque and power when I mash the gas. It's with a TH400 and 3000 converter. Mechanical secondaries. Did have to play with the jet size. Good luck.
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 22
Likes: 0
@73'vette
im wondering a little about your total timing, on the same eninge.
everywhere i read vortec heads onla need 32* total.
how much initial you set ?
@ marz
wanne get about 400 HP
light car, about 2600 lbs. with a 5 speed TKO (1st 3.27 ), 3.05 rear end on 15" wheels with 265/60 tires.
im wondering a little about your total timing, on the same eninge.
everywhere i read vortec heads onla need 32* total.
how much initial you set ?
@ marz
wanne get about 400 HP
light car, about 2600 lbs. with a 5 speed TKO (1st 3.27 ), 3.05 rear end on 15" wheels with 265/60 tires.
Burning Brakes
Joined: May 2006
Posts: 774
Likes: 1
From: Round Rock Texas
My timing I set at 36 and it liked a little more, but I left it at 36. I also plugged the vacuum advance and it liked that even more. If yours is anywhere close to the 400hp range I would go for the 750 cfm carb. That along with Hooker long tube headers for more torque and you should be in business.
Thread Starter
Heel & Toe
Joined: Feb 2008
Posts: 22
Likes: 0
how much vacuum you add ?
i think i will start at 9* ini and 34* total.the msd dizzy 8360 have 18 - 21 - 25 - 28 degree bushings for mech. advance.
and about 10* vac. at the manifold port.
you mean the 750 speed demon or a holley double pumper ?
i had a look at the 650 double pumper Holley 0-82651.
i only can use shorty headers because its to close to the frame.
i think i will start at 9* ini and 34* total.the msd dizzy 8360 have 18 - 21 - 25 - 28 degree bushings for mech. advance.
and about 10* vac. at the manifold port.
you mean the 750 speed demon or a holley double pumper ?
i had a look at the 650 double pumper Holley 0-82651.
i only can use shorty headers because its to close to the frame.
Racer
Joined: Nov 2006
Posts: 495
Likes: 1
From: Lubbock TX
I also have the Yearone 350. I was using my stock q-jet and had some trouble, but I rebuilt it with a cliffs ruggles kit and now it runs great except for off idle stumble when I floor it. I think my total timing is about 32*, but I think I am getting too much mech adv. I was afraid to go over 32* total with vortec heads and I can only get 91 octane here.
What vacuum advance can are you guys running with this engine? I can get mine to pull about 11-12* vacuum.
I recently bought an LM-2 wideband o2 sensor and just started tuning with it. I found out that I was pretty rich all the way around, probably losing WOT power. I haven't spent much time trying to get it in a better range, but I'll see how lean I can go without detonation or surging at cruise.
Sean
What vacuum advance can are you guys running with this engine? I can get mine to pull about 11-12* vacuum.
I recently bought an LM-2 wideband o2 sensor and just started tuning with it. I found out that I was pretty rich all the way around, probably losing WOT power. I haven't spent much time trying to get it in a better range, but I'll see how lean I can go without detonation or surging at cruise.
Sean
Advanced
Joined: Jun 2006
Posts: 65
Likes: 0
From: SHADY SPRING WV
I have the speed demon 650 with mech. secondaries. No off idle hesitation and great acceleration when the secondaries kick in. With the street avenger with vacuum secondaries you dont feel the surge because they only open with the amount of vacuum you have. You can change to a lighter spring to make them open quicker but it still doesn't compare to mech sec. I had to set my timing to 34 degrees total with no vacuum advance because of spark knock. I am running hooker full length headers with 2.5 in true duals and turbo mufflers. It isn't loud but it sounds good.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
I also have the Yearone 350. I was using my stock q-jet and had some trouble, but I rebuilt it with a cliffs ruggles kit and now it runs great except for off idle stumble when I floor it. ...
I recently bought an LM-2 wideband o2 sensor and just started tuning with it. I found out that I was pretty rich all the way around, probably losing WOT power. I haven't spent much time trying to get it in a better range, but I'll see how lean I can go without detonation or surging at cruise.
Sean
I recently bought an LM-2 wideband o2 sensor and just started tuning with it. I found out that I was pretty rich all the way around, probably losing WOT power. I haven't spent much time trying to get it in a better range, but I'll see how lean I can go without detonation or surging at cruise.
Sean
The idle mixture affects off idle & there is limited adj. towards rich.
The accel. pump has adj. holes on the lever & another can be drilled.
Racer
Joined: Dec 2003
Posts: 399
Likes: 0
From: Haslet,Texas
I finally got a chance to play around with the jets a little. I ended up with 75 secondary and 69 primary. I did 7 passes at the track tonight with a best of 8.87. Once I find someone who knows how to weld stainless steel, I'll get a bung welded into my collector. From there, I will use a friend's LM1 and tweak the carb further. I'm hoping to get the times closer to 8.5 sec. (1/8 mile track)
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
You really need better exhaust first. The Dynomax Corvette SB Cerama-Coat full length headers fit & flow great.
...
this is one thing where i loose some power for sure.
at the moment i use some cc90 sanderson blockhugger headers into a short 2 1/2" pipe into a sidepipe.
i know its not the best way to create power but i have to use the short headers because my exhaust is to close to the frame.
if i would use some long headers i have to install the pipe under the frame.
while driving they sometimes would hit the floor and will be damaged.
there is not enough room to go this way.
...
this is one thing where i loose some power for sure.
at the moment i use some cc90 sanderson blockhugger headers into a short 2 1/2" pipe into a sidepipe.
i know its not the best way to create power but i have to use the short headers because my exhaust is to close to the frame.
if i would use some long headers i have to install the pipe under the frame.
while driving they sometimes would hit the floor and will be damaged.
there is not enough room to go this way.
...