I'm in the process of gathering the parts for my new motor. Block and heads went to the machine shop last week. It will be a .030 over 454 with around 10:1 compression (still trying to decide exactly what pistons to go with), 291 heads, factory LS6 intake, BTE street/strip stall converter and 4.00 rear gear. Any recomendations for a carb? I have an old Holley 780 that I've been contemplating trying since I already have it. Is that too small?
454 w/ Voodoo 60204 - what carb?
70ChevelleRagtop
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I'm in the process of gathering the parts for my new motor. Block and heads went to the machine shop last week. It will be a .030 over 454 with around 10:1 compression (still trying to decide exactly what pistons to go with), 291 heads, factory LS6 intake, BTE street/strip stall converter and 4.00 rear gear. Any recomendations for a carb? I have an old Holley 780 that I've been contemplating trying since I already have it. Is that too small?
But make sure you jet it slightly lean,have a p/valve thats correct for the cam's lower intake vacuum,and float lvls are set well for 1st fireup.
I suggest that to ensure the carb is not calibrated too rich which could possible cause a fuel wash issue resuling in poor ring seating that we see here in t/chevelle every once in a while.
Scott
I suggest that to ensure the carb is not calibrated too rich which could possible cause a fuel wash issue resuling in poor ring seating that we see here in t/chevelle every once in a while.
Scott
My build is similar to yours, I just used the 60203 Lunati cam. On the dyno 2 weeks ago, with my 750 Vac secondary, I got 284 hp to the rear wheels. Bolted on a friend's 800 double pumper, and the hp went up to 333. A 50 hp increase by doing nothing else.
I'm shopping for a double pumper now, after seeing those kind of improvements. The dyno run is in my sig.
I'm shopping for a double pumper now, after seeing those kind of improvements. The dyno run is in my sig.
John,
If you had a few less projects or more time....
You could have made the modifications to your 3310 that I had suggested.
Same ones the guy from Alger had:
74/84 jetting , tall black secondary spring.
Rear metering plate replaced with a metering block.
The 3310's rear metering plate is a wimpy 76 jet and the stock spring barely lets the secondaries open. The stock set-up leaves a lot of power on the table.
Ask 'mr 4 speed' what his Chevelle runs with his 3310.....and 3.31 gears
If you had a few less projects or more time....
You could have made the modifications to your 3310 that I had suggested.
Same ones the guy from Alger had:
74/84 jetting , tall black secondary spring.
Rear metering plate replaced with a metering block.
The 3310's rear metering plate is a wimpy 76 jet and the stock spring barely lets the secondaries open. The stock set-up leaves a lot of power on the table.
Ask 'mr 4 speed' what his Chevelle runs with his 3310.....and 3.31 gears
Dana,try your 750..powervalve will be important as Scott mentioned due to the long duration.
John,I have tested a 3310 vs. 4779 at the track and the 3310 was one MPH faster than the 4779..both carbs where jetted very close (3310: 74/84 4779:73/83)
Sounds like your 3310 is stock out of the box.
My car runs mid 12's @ 108 MPH thru the exhaust with 3.31 gears
John,I have tested a 3310 vs. 4779 at the track and the 3310 was one MPH faster than the 4779..both carbs where jetted very close (3310: 74/84 4779:73/83)
Sounds like your 3310 is stock out of the box.
My car runs mid 12's @ 108 MPH thru the exhaust with 3.31 gears
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Thanks guys. I'm going to put a kit in this carb and try the suggestions you guys have made. I already have the secondary metering block on this carb.
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This kinda findings makes me want to run a DP, but from my obseravtions, it seems that vac secs dont do well on the dynos. Not sure if there down on power in general, or just the vac secs dont take to the way dynos load the motor. But, many times the vac sec carbs will ET/MPH close to the DP's. I know a car should '60 better with a DP.
I dont know about a "tall black" spring, but the black spring wont open the secondaries all the way on a 3310, at least not till very high rpms.
Vince,
Good pal TC member DAVE had this set..... 13.0/109 with 3.31s second outing, 1st outing this year, black spring. I run the Yellow springs on RatVette...I believe 'mr 4 speed' does too.
When my Super Budget 454 gets together and inside my 70 Elky, my baseline will be 73/83 /yellow or 74/84/yellow
I believe Holley SCREWS the 3310 buyers with their stock carb tunes so they are FORCED to buy assorted upgrades. The stock spring requires you to be driving a fully-loaded cement truck up a 8% grade in order for the secondaries to open!
Good pal TC member DAVE had this set..... 13.0/109 with 3.31s second outing, 1st outing this year, black spring. I run the Yellow springs on RatVette...I believe 'mr 4 speed' does too.
When my Super Budget 454 gets together and inside my 70 Elky, my baseline will be 73/83 /yellow or 74/84/yellow
I believe Holley SCREWS the 3310 buyers with their stock carb tunes so they are FORCED to buy assorted upgrades. The stock spring requires you to be driving a fully-loaded cement truck up a 8% grade in order for the secondaries to open!
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Yeah I dont recommend the black spring unless your looking for mileage.
I run the yellow also, in fact, my car even liked the white spring, even with ET street's. This was the 770 Avenger, which is essentially a purdy 3310. The black spring is the stock spring, which I wouldn't run. I figure Holley installs these so folks with low HP 305's and 350's dont bog out their motors.
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Unless you are looking for a "correct look" the 569 low profile intake will leave some horsepower on the table....any aftermarket dual plane intake or 163 GM intake will make more power. Most guys switched out the low profile unit back in the day...I would estimate 15-20 hp gain....
wilma
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:yes: I know that but thanks anyway. I'll never afford a real LS-6 car so this is my version...I'm not out to be the baddest car in the neighborhood. My drag racing days are long gone!
Depends on the app. I have the same cam, iron oval ports, and 496 cubes. I am running an 800 Eddy Thunder. Throttle response is great. I still need to finish fine tuning, but it runs great, idles good, and made 492 hp and 565 torque. With a airflow meter on the engine during dyno testing, showed about 720 cfm. A good street carb and tunable. I will likely pick up more powr if I switch to a Holley.
E.
I always wondered about the 163 vs. 569..nobody has any timeslips to prove a HP gain or loss..a 569 looks like a 163 upside down
I have heard they both have the same plenum volume.
I can tell you there is no ET or MPH difference between a Performer 2-0 vs. Performer RPM with my combo.
I might have to try a Performer RPM vs. 569 swap one of these days...
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Holley 770 SA with a 1" open plate worked best on my combo.
Dyno showed air flow was near optimum
Dyno showed air flow was near optimum
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Since I finally have my convertible back on the road, I thought I would update this post. I ended up going with a Holley 4492 carb (restored thanks to Eric at Vintage Muscle Car Parts :thumbsup: ) on my fresh 454. I'm very pleased with how it runs. The Lunati 60204 is a little low on vacuum at low idle for the power assist brakes but I can live with that. Overall it performs very well with my combination. Since the motor is still getting broken in, I haven't thrashed on it extremely hard however for a '70 convertible that I drive quite often, there is more than enough motor under the hood to draw attention to the car! It has nice lumpy idle and sounds great via the Parts Place Inc. reproduction dual exhaust. I'm going to need new rear tires soon! :thumbsup:
Build Specs:
454 .030 over
Factory steel crank
SpeedPro Hyper-tech pistons with .100 dome mounted on thumb-rods
Stock 291 heads
Winters 569 (LS6 / L78) intake
Holley 4492 780cfm carb
Factory cast-iron exhaust manifolds (non-functioning A.I.R. system coming soon)
Parts Place Inc. reproduction dual exhaust
Lunati 60204 (with the corresponding valve springs)
Turbo 400 (slightly massaged with auto-shift or full manual)
BTE street/strip converter
4.10 12-bolt posi
![Image]()
Build Specs:
454 .030 over
Factory steel crank
SpeedPro Hyper-tech pistons with .100 dome mounted on thumb-rods
Stock 291 heads
Winters 569 (LS6 / L78) intake
Holley 4492 780cfm carb
Factory cast-iron exhaust manifolds (non-functioning A.I.R. system coming soon)
Parts Place Inc. reproduction dual exhaust
Lunati 60204 (with the corresponding valve springs)
Turbo 400 (slightly massaged with auto-shift or full manual)
BTE street/strip converter
4.10 12-bolt posi
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Good to see a follow up. A lot of these threads get started but then we never hear how it ended up. Nice job. Enjoy it.
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Thanks. The motor actually has been assembled for several years. I got onto a slippery slope with the rest of the car and one thing lead to another and I ended up with a lot of it in pieces!
:thumbsup:
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