[mchell]

Originally Posted by yellow1098

So my engine is finally done here is the combo……..
70 4 bolt main block, 461 , compression 10.2, 340 Cfm eheads,, port matched northwind intake, camshaft: 248 intake 254 exhaust 620 gross lift 112 lobe separation.

I am also running a Holley terminator x with a 1300 cfm throttle body

The engine was Dynoed with only a 750cfm carb as they didn’t have the setup to run efi on the Dyno and it made 551 hp and 555 torque at 6500 rpm

When I bought my combo from butler the parts combo was put together with the goal of 650hp so I was about 100hp shy of that

My questions is how close will I get to that with my 1300 cfm throttle body compared to the obviously to small 750 carb?

The goal with the Dyno was only to break the engine in properly before I put it in the car which I accomplished and everything ran great! I just wanted to get your thoughts on how much HP and torque I lost with the engine being under carbed compared to what my goal is.

Thanks as always

My similar combo: less head flow(295 dport), rpm, quadrajet…made 555/577 on the engine dyno. Pulls to 6k. Peak hp was 5800 I believe. Didn’t do a thing to it. Pure tractor motor. Didn’t care if timing was 30-36….You could certainly achieve higher peak dyno #s with carbs/intakes/spacers …cam would certainly help

I swear I just watched a hp tv episode where they installed a butler crate 455….supposed to see well north of 500hp….don’t recall that they were close

Dyno’s……..

[slowbird]

Originally Posted by Gach

Maybe 30-35 more hp. The cam just isn’t enough. Need something in 260 range duration.

No way is it worth 30-35hp. A 455 isn't remotely in need of that much cfm! And 260° duration is enough for 700+hp

[Gach]

iA 455 isn't remotely in need of that much cfm! And 260° duration is enough for 700+hp

The bottom line is he’s asking if it’ll make 650 hp. No it won’t. I said MAYBE 30-35 more if any. With 1300 cfm deal.

[slowbird]

Originally Posted by Gach

The bottom line is he’s asking if it’ll make 650 hp. No it won’t. I said MAYBE 30-35 more if any. With 1300 cfm deal.

He has the basic parts to make 650hp on paper anyway. I agree just swapping over to his throttle body isn't getting him to his goal.
Like others said 550+ is loads of fun on street and plenty for most.

[scott70]

Originally Posted by mchell

My similar combo: less head flow(295 dport), rpm, quadrajet…made 555/577 on the engine dyno. Pulls to 6k. Peak hp was 5800 I believe. Didn’t do a thing to it. Pure tractor motor. Didn’t care if timing was 30-36….You could certainly achieve higher peak dyno #s with carbs/intakes/spacers …cam would certainly help

I swear I just watched a hp tv episode where they installed a butler crate 455….supposed to see well north of 500hp….don’t recall that they were close

Dyno’s……..

Tony angelos firebird was on hagerty and made like 340 rwp. He seemed disappointed.

[Murf]

Originally Posted by scott70

Tony angelos firebird was on hagerty and made like 340 rwp. He seemed disappointed.

Yeah, he was way disappointed but it is a low comp blower motor set up.

Murf

[yellow1098]

Thanks for the info boys! I’ll get you the dyno sheet……even if I get over 600 with my throttle body and a tune I’ll be happy….the shop that had the dyno wasn’t very technical so I wonder about everything …..it’s ok though the point was just to check everything and get her broken in right before I messed with the efi

Plus I was planning on giving it alittle spray anyway

[25stevem]

Maybe I can shed more light on to what may also having a effect on the level of power being made here by the OPs combo .

Way back in 2014 I had the very good fortune to spend about 10 minutes talking to David Vizard about the need for a certain cfm carb to produce a given level of power.

He cited to me a example of 2 BBC motors that both made 1100 hp, give it take 4 to 5 hp.

These 2 motors where both the same cid and used the same cam and the same pistons producing the same compression.

The only difference was the heads and intake manifold used.

So they both where extremely close to being the exact same build.

The main difference was how much fuel per hour each motor needed to make that 1100 hp which ties right in with the needed cfm rating of the carb used.

One BBC needed only 1260 cfm or like 5.2 pounds of fuel per hour, and the other needed 1450 cfm , or 6 pounds of fuel per hour.

These two differences where basically related to the how equal the fuel distribution was per cylinder that the intake manifold used produced, and how good the cylinder heads where in shredding up streams of wet flow ( wet flow management ) back into a burnable useful state.

As happy as I am that we have very useful formulas to get us to base line numbers, many of them assume ideal conditions and not the variations that take place in the real world!

[slowbird]

Originally Posted by 25stevem

As happy as I am that we have very useful formulas to get us to base line numbers, many of them assume ideal conditions and not the variations that take place in the real world!

Theory is fine, real world experience (dyno and track) are what really matters

[PunchT37]

Originally Posted by slowbird

Theory is fine, real world experience (dyno and track) are what really matters

Facts.

Kinda like folks who think they can work as a mechanic, for a living, by watching youtube videos.

[Stan Weiss]

Originally Posted by 25stevem

Maybe I can shed more light on to what may also having a effect on the level of power being made here by the OPs combo .

Way back in 2014 I had the very good fortune to spend about 10 minutes talking to David Vizard about the need for a certain cfm carb to produce a given level of power.

He cited to me a example of 2 BBC motors that both made 1100 hp, give it take 4 to 5 hp.

These 2 motors where both the same cid and used the same cam and the same pistons producing the same compression.

The only difference was the heads and intake manifold used.

So they both where extremely close to being the exact same build.

The main difference was how much fuel per hour each motor needed to make that 1100 hp which ties right in with the needed cfm rating of the carb used.

One BBC needed only 1260 cfm or like 5.2 pounds of fuel per hour, and the other needed 1450 cfm , or 6 pounds of fuel per hour.

These two differences where basically related to the how equal the fuel distribution was per cylinder that the intake manifold used produced, and how good the cylinder heads where in shredding up streams of wet flow ( wet flow management ) back into a burnable useful state.

As happy as I am that we have very useful formulas to get us to base line numbers, many of them assume ideal conditions and not the variations that take place in the real world!

Steve,
This does not make any sense to me. The only thing that I can think of that those number would be close to is BSAC.

This a screen from a program I wrote with David Vizard.

Stan

[25stevem]

Yes. The BSAC factor.

[ta man]

Originally Posted by yellow1098

Thanks for the info boys! I’ll get you the dyno sheet……even if I get over 600 with my throttle body and a tune I’ll be happy….the shop that had the dyno wasn’t very technical so I wonder about everything …..it’s ok though the point was just to check everything and get her broken in right before I messed with the efi

Plus I was planning on giving it alittle spray anyway

I can't see it making less than 600 fully tuned.

[PAUL K]

Fwiw.... Just because a head is CNC ported and flows X amount doesn't guarentee it's a good port or even flows that CFM. We have seen some real crap CNC ported heads as of over the years. We've also seen some builds using these heads fall way short of their power goals.

Another thing, just because the guy selling the parts says it'll make X amount of power, it isn't a guarantee it will. In forty years I have NEVER gotten any power number from a knowledgeable cam guy and it took me several years to realize why.

[slowbird]

Originally Posted by PAUL K

In forty years I have NEVER gotten any power number from a knowledgeable cam guy and it took me several years to realize why.

Well you need to share why Paul, why?

[Cliff R]

Just looking at the engines I've done here 230 @ .050" will get you 500hp with 260cfm heads.

236 @ .050" will get you 550hp with 290-310cfm head flow.

260 @ .050" was worth 650hp with 330cfm head flow (very well prepared Edelbrock round port heads)..

I don't see 248@.050" ever getting you to 650hp even with 20cfm more head flow. Probably closer to 590-610hp with 10 to 1 compression and ideal intake, carb and exhaust system.......FWIW......

An added note here. I was involved but did not build a 455 that ended up making 612hp. It used early KRE aluminum "D" port heads ported to 310cfm. Can't remmeber the exact cam specs but it was a solid roller grind around 245/255 @ .050".. Two different intake/carb combo's were ran on that engine while it was on the dyno.

The new (at that time) Tomohawk intake topped with a 1" spacer and 850cfm carb. We also ran a Victor/Dominator on it. There much bigger Victor/Dominator set-up was only worth about 10-12hp and we made quite a few pulls with both set-ups to get those numbers.

I've also seen the T-II intake, 1" spacer and 850cfm carb set-up rival the Victor/Dominator at that power level on several other 455 builds.

With all that said I don't see the intake/carb being a huge restriction on what you are doing........

[slowbird]

Originally Posted by Cliff R

Just looking at the engines I've done here 230 @ .050" will get you 500hp with 260cfm heads.

236 @ .050" will get you 550hp with 290-310cfm head flow.

260 @ .050" was worth 650hp with 330cfm head flow (very well prepared Edelbrock round port heads)..

I don't see 248@.050" ever getting you to 650hp even with 20cfm more head flow. Probably closer to 590-610hp with 10 to 1 compression and ideal intake, carb and exhaust system.......FWIW......

An added note here. I was involved but did not build a 455 that ended up making 612hp. It used early KRE aluminum "D" port heads ported to 310cfm. Can't remmeber the exact cam specs but it was a solid roller grind around 245/255 @ .050".. Two different intake/carb combo's were ran on that engine while it was on the dyno.

The new (at that time) Tomohawk intake topped with a 1" spacer and 850cfm carb. We also ran a Victor/Dominator on it. There much bigger Victor/Dominator set-up was only worth about 10-12hp and we made quite a few pulls with both set-ups to get those numbers.

I've also seen the T-II intake, 1" spacer and 850cfm carb set-up rival the Victor/Dominator at that power level on several other 455 builds.

With all that said I don't see the intake/carb being a huge restriction on what you are doing........

If I can make 620+ with 1 pull (no carb tuning or playing with spacers) and alum d-ports with 243-249 cam then I see no reason real close to 650hp can't be achieved with a little more can and a better exhaust that the round ports offer.

[tom s]

We made 585 with a 455 and Daves 290CFM D ports with 245-252 hyd roller cam.Joe Shermans dyno.Tom

[Stan Weiss]

I would still like to see a dyno sheet.

Also a flow sheet for the head might help. It stated they flow 340 cfm but at what lift. As stated the cam has 0.620"

Stan

[ta man]

Originally Posted by tom s

We made 585 with a 455 and Daves 290CFM D ports with 245-252 hyd roller cam.Joe Shermans dyno.Tom

I'm at 127.5 mph with Dave's 310cfm heads and his 235/245 cam at 3700 lbs what ever that works out to? 590?