Have a 454, 30 over, straub cam .620/.620 Lift 233/233 .050 109 Sep, afr 265 heads 109cc, 10:1 compression. Currently have a air gap on it, wasn't sure if a single plane would be better like a VictorJr. My goal was to have 620HP. Saw a Motor trend article saying a very similar setup made 622HP on a dyno. Think that's realistic or am i more in the 540 range? plan on going with a 950 holley. How do you think a sniper setup would be on it? It should be done in about 3 months, shop is backed up with other builds they are very busy this time of year.
So what do you think about this setup
layz
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Have a 454, 30 over, straub cam .620/.620 Lift 233/233 .050 109 Sep, afr 265 heads 109cc, 10:1 compression. Currently have a air gap on it, wasn't sure if a single plane would be better like a VictorJr. My goal was to have 620HP. Saw a Motor trend article saying a very similar setup made 622HP on a dyno. Think that's realistic or am i more in the 540 range? plan on going with a 950 holley. How do you think a sniper setup would be on it? It should be done in about 3 months, shop is backed up with other builds they are very busy this time of year.
I unfortunately cannot comment on your goals but can offer if you do go with sniper, go ahead and add the progressive linkage to your cart when you do. Just did a sniper 454 and it sucked the blades down so tight you damn near couldn't drive the car without boiling the tires when the blades would pop open. The progressive linkage fixed the issue and made it like butter to drive again.
What does Chris Straub have to say about your HP goal?
Check this out:
454 Build and Dyno Results (600+ HP!)
Hey y’all, I’m new here so I hope I’m doing this right. My dad, brother and I just finished building our first Big Block Chevy. Here’s a list of parts we used: 454 4-bolt main block with main studs AFR 290cc heads Comp custom hyd. roller (237/241 @.050; .671” / .676” lift / 106 LSA) L2465-F...
www.chevelles.com
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100% capable of 600+ horsepower. I would run the air gap + 1" open spacer (if your hood allows it).
I also fully recommend the Sniper EFI. Keep in mind, EFI is only as good as your tune. It's not uncommon for dyno shops to dyno an engine with a carb because it is much much easier to get a good baseline vs EFI. I know a guy that recently found something like 60 rwhp from a dyno shop tuning on his EFI. So don't get too alarmed if it feels a bit down on power out of the box with the EFI.
Also don't get too invested in dyno numbers. There is a shop here that always puts out HUGE numbers, and yet the car's never seem to translate that power in the real world. Any dyno shop can inflate their numbers. I hate seeing dyno sheets with coolant temps around 130F for example. You won't see that power when you're at normal operating temps of around 180. Or worse would be improper correction factors. Chassis dyno shops using STD instead of SAE.
I also fully recommend the Sniper EFI. Keep in mind, EFI is only as good as your tune. It's not uncommon for dyno shops to dyno an engine with a carb because it is much much easier to get a good baseline vs EFI. I know a guy that recently found something like 60 rwhp from a dyno shop tuning on his EFI. So don't get too alarmed if it feels a bit down on power out of the box with the EFI.
Also don't get too invested in dyno numbers. There is a shop here that always puts out HUGE numbers, and yet the car's never seem to translate that power in the real world. Any dyno shop can inflate their numbers. I hate seeing dyno sheets with coolant temps around 130F for example. You won't see that power when you're at normal operating temps of around 180. Or worse would be improper correction factors. Chassis dyno shops using STD instead of SAE.
I spoke to him first said i would like a 600 HP 454 and how realistic was that? We had a conversation and he said this should get me there if not close. I mean the guy seems to know what he's talking about but wanted a second opinion.What does Chris Straub have to say about your HP goal?
Check this out:
454 Build and Dyno Results (600+ HP!)
Hey y’all, I’m new here so I hope I’m doing this right. My dad, brother and I just finished building our first Big Block Chevy. Here’s a list of parts we used: 454 4-bolt main block with main studs AFR 290cc heads Comp custom hyd. roller (237/241 @.050; .671” / .676” lift / 106 LSA) L2465-F...
I have that same cam from Chris, in my 434, 396, .040, 4 inch stroke, AFR 265’s. When I spoke to a Chris, he said I should expect 30-40 HP gain and similar torque to the 543/550 I was making previously. Unfortunately, I didn’t have it dyno‘d at the time. dyno was had a software issue, and I was impatient. I am also running a sniper setup, and it runs flawlessly. I’m not using the timing control, using MSD with a 6al digital. There’s no reason you shouldn’t be in the 600 ballpark with the extra cubes.I am running an air gap intake as well. I didn’t use the progressive linkage, it was touchy at first, but self tuning must have calmed it down. When I switched from the carb 850 quick fuel) to the sniper i notices smooth power, less rich smell, simple starting. I used bought the kit, but added a sniper fuel tank for the internal pump set up. Very happy with the combo.
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I think you will be in the 580 range.
The 950 carb actually flows less than the 850. Ask about wet flow.
Good you are going 454. It keeps torque down which saves you a ton of money on suspension, transmission, torque converter and other parts. 620-700 hp range and you are spending mucho money to make it work at the track. If you are only street driving with normal street tires you would be ok.
Rick
The 950 carb actually flows less than the 850. Ask about wet flow.
Good you are going 454. It keeps torque down which saves you a ton of money on suspension, transmission, torque converter and other parts. 620-700 hp range and you are spending mucho money to make it work at the track. If you are only street driving with normal street tires you would be ok.
Rick
If you have good pistons with a modern ring pack, that will make 600hp all day. Use a performer rpm air gap with a 1" open spacer.
As for the carb, which 950 is it? As there are numerous variations. I can say that out of the box, any holley/quick fuel with billet metering blocks don't run that great, if you have ever driven a car with a car that is tuned right.
For the money that the higher end mass produced carbs are now, for almost the same cost you can get a custom made billet carb that will actually do what it is supposed to. Dominic Thumper and Mark Whittener (Lightning Racing carbs) are two guys I have used. Great quality, and service.
As for the carb, which 950 is it? As there are numerous variations. I can say that out of the box, any holley/quick fuel with billet metering blocks don't run that great, if you have ever driven a car with a car that is tuned right.
For the money that the higher end mass produced carbs are now, for almost the same cost you can get a custom made billet carb that will actually do what it is supposed to. Dominic Thumper and Mark Whittener (Lightning Racing carbs) are two guys I have used. Great quality, and service.
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18,738 Posts
Cant comment on lift, but my combo has less, and less duration and makes OVER 600 hp. Think it'll run just fine, and have enough vacuum to run a Sniper OK. ( although unsure I'd spend the $$ on EFI yet please do if you prefer, I am a Holley shareholder! )
Honestly i was just going to throw this on Holley 0-80496-2 950 CFM Classic HP Carburetor-Aluminum i have a 750 holley that was on it before but figured I would be choking it out. I actualyl do want to run a sniper instead of carb but then i gotta get a tank from holley and all the extra stuff. Not that i don't want to it's just going to delay me getting up on the motor LOL. Hmm maybe i'll chek them out thanks.
For the sake of simplicity, I'd lean towards breaking in the engine with a known good carburetor.
EFI is a whole 'nother project.
Look up "Holley Sniper EFI Owners and Tech" on facebook.
Read a ton of posts, there's a lot to learn.
Best of luck.................DC
EFI is a whole 'nother project.
Look up "Holley Sniper EFI Owners and Tech" on facebook.
Read a ton of posts, there's a lot to learn.
Best of luck.................DC
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6,021 Posts
To me the larger 4150 carb is a better choice. Tuning any carb is key as well as ignition.
Holley established the size and flow for most of their style carbs and that is what most custom use. The 950 actually flows less than the 850. Always ask about wet flow number.
Rick
Holley established the size and flow for most of their style carbs and that is what most custom use. The 950 actually flows less than the 850. Always ask about wet flow number.
Rick
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If you have a known good 750 dp, use that. I ran 11.1 @ 119mph with one on a 427.
Rick
Rick
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I dont have my Sniper anymore, but ill second the benefit of the progressive linkage. Made a huge improvement on drivability of my mild small block. Its a shame it isnt the standard setup, nor that they dont include the silly little rod in the $1000+ kit.
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In 1968-9 the 6 pk dodges and plymouths had mechanical linkage and were not city friendly so in 1970 they went to progressive. From what I remember they ran off the center carb until about 35 mph then the other 2 kicked in. Would have not been fun in traffic. I put a $20 deposit on a lift off hood superbee but my dad said NO.
Rick
Rick
That carb will be fine. Still some issues, but not near like the new whiz bang best ever from Holley. It's the good 750 venturi and 1.75" baseplate. Flow about 820 and great response/shift rpm recovery.
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7,406 Posts
I had a 400hp Vette tri-power that was converted to mechanical linkage with 3 pumper carbs, it was a dog without any converter. Great from a 50mph roll🤣
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2,365 Posts
My question is why a single pattern camshaft? I assume Chris specified that cam with all your information.
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