Had my standard b1’s race ported by Barton many years ago and flowed them a few days ago. The exhaust only flows 250 cfm at 550 lift at 25”. Valve size is 1.785. No gain from 550 to 800 lift. 2.300 intake maxes out at 368 cfm at .700 lift at 25”. This is an all out race motor with a roller cam. Is there more flow to be gained? This 451 race motor only made 794 hp at 7300 and 599 tq at 6300. What should I do?

That converts to @28 intake 389.5, Ex @ 28 264.6,, Take it to the track & see what it runs.

Im no head guru but my maxed out SR's flow 368 @ .750 lift . Yours should be better or capable of being better.

Don't worry about the exhaust.

Don't kill yourself over flow numbers. If the valve job is correct and the port work wasn't done with a body grinder you'll be fine.

Me thinks the machine shop, flow tester, goof up something on your heads testing them
I've had a bunch of different BB Mopar heads flow from bone stock 906 and 1963 M.W. heads up to several different sets of MCH CNC ported 440-1 and one set of B1 ported by Koffels. the CNC ported 440-1 with 2.250 intake valves flow right at 370 CFM at 28 inches at .700 valve lift on the intakes on a Super Flow 600 bench with a 4.375 bore and the B1 heads on the same bench with the same bore size flowed 420 CFM at .700, 430 CFM at .900 and at 1.00 lift
If I was you and wanted to learn more I would call Bob at MCH (568-468-7914) and talk to him about your heads. I'm sure Ray Barton did a decent job on your heads but I don't know what you wanted them to accomplish originally

Who flows heads at 25"?

Kevin

Local mopar racer. Says it’s makes more realistic numbers. Didn’t know this till I picked them up. Anyway, this motor should make more power buts it’s not. The 68 dart only runs 9.90 at 137 mph at 3100 lbs

Many do. That's why I said don't get ate up over flow numbers.

It's not like Barton is stupid.

That’s pathetic. Something wrong big time with that combo.

The combo is off if it really makes 800. What are the short times from your Dart?

I doubt a 451 with B1 heads in a 3100lb car needs the heads to be any “bigger”(more porting).

I’m not sure if this is still the case, but SuperFlow used to have their flow benches calibrated at 25”, so some shops used that as the test pressure.

Start by putting a 4.25"-stroke crank in it to make better use of those big ports.

I'd like to see more about the combo. What cam and compression, transmission converter and gear?

The combination is a 15:1 451 cid with b1 original heads, sheet metal intake with two 1050’s, roller cam with .845 intake 285 duration and .766 exhaust and 299 duration ground on 110 lobe separation. Exhaust is 2 to 2/18 equal length. Trans is a 727 with a brake, 5500 stall, 14x32 and 5:13 gears. With the exhaust limit of .550 lift, I think the two dominators are killing the motor.

did barton do the whole motor ???

Yes and dynoed it also
Max hp is 794 at 7300
Tq is 599 at 6300

I think the converter is the issue. I run way more stall speed and less cam in my 572, 6100 flash stall. That is a lot of cam for a small motor. With the right converter that thing should run pretty decent. I'm sure with that cam and heads it would be even better on a 528/540 short block.
Doug

Motor makes peak tq at 6300........ and you have a 5500 converter.
That’s the first thing I’d be addressing.

Converter probably is 6000. I sent the dyno sheet to the company

do you have a way to see the flash during a run and what it rpm's at the shifts? I have a play back box on my tach which was great for this. That will show what the converter is doing.

First thing I would do before I spent a bunch of money chasing my tale with the motor combo is, pull the motor and bring it to a nearby dyno service that’s known for legit numbers and retest the motor.

A fresh set of dyno numbers would verify you have what you think you have, as well as where the peaks are occurring.
I have re-tested several motors where the owners have spent thousands of dollars trying to get the car to go as fast as their dyno sheet said it should....... only to find after re-testing that it didn’t have the power they were told, and the car was actually running just what it should.

You need to test the converter flash.
What the converter “should” be and what it actually is could be very different.

I’m not a converter builder, but if the motor really makes peak tq at 6300, you’re going to want like 6500 stall.
I can’t imagine an 8” converter flashing to 6500 behind a 451, and still be efficient enough to provide an adequate level of lock up going down the track in a 3100lb car(unless you were shifting at like 8200+).
I don’t know what you have, but it sure sounds like a combo that would need a 7” unit to meet that criteria.

Well I gotta ask what B1 head is this? An original, or a BS? For a "race ported" original those would be sub standard numbers for sure. Also an original on a 451 is a LOT of head and I'd guess wants a LOT of RPM to be happy. Been there done that as my first B1 engine was a 451. Also you are not running anywhere near almost 800hp worth of MPH, you are likely close to 10MPH off for that HP and weight. So something is quite a bit off in the combo and numbers

just to put this out there... I have a pair of originals that were done by a very reputable shop, per the previous owner, that go 372cfm at .650 on my bench. Point being the port job, if any, could be the issue here. Maybe cross section/cubic inch/flow, makes for a lazy engine. Not to mention the 2 dominators.

Everything is apart right now. I do shift at 8000 with this 8” converter. Maybe it wants more. I’m just trying to see if one of my problems is the exhaust. There is no flow gain above.550 lift with these b1 originals. It seem odd that a race head tops out at this lift.

With your combo 32x5.13 gear and only 648fwhp@3100 this is what the ticket would look like>

60 Foot E.T. : 1.36
1/8 Mile E.T. : 6.19
1/8 Mile Trap Speed : 109.76
1/4 Mile E.T. : 9.81
1/4 Mile Trap Speed : 137
1/4 Mile Trap RPM : 7,360+slip

At 790hp it would be

60 Foot E.T. : 1.28
1/8 Mile E.T. : 5.80
1/8 Mile Trap Speed : 117.25
1/4 Mile E.T. : 9.19
1/4 Mile Trap Speed : 146
1/4 Mile Trap RPM : 7,862+
just for reference, The Moroso slide rule shows less hp.

Thanks for that info

A 451 pump gas engine with Trick Flow heads will run 9.90's in a 3100 lb car if everything is working right so that combo is way, way off somewhere.

Fast is correct, get the engine on a known good dyno to sort it out. If the engine is all apart then look it over for clues. Maybe the Dominators were set up wrong and the engine was going down the track at 9:1 air fuel ratio? Maybe the firing order was switched up? If it was my engine I'd get rid of the sheet metal intake and the carbs and put a single 4bbl on there. I bet it goes faster and works better.

Also sounds like the drivetrain might not match the engine. I know Mazzolini used to run a 383 with B1 heads and he shifted at the moon. Just crazy RPM with those big heads on a smaller engine.

Were the ex ports tested with the appropriate sized flow tube attached?

I really wouldn’t too be concerned with the ex flow flatlining at .550 lift........I’ve seen heads that came off good running hemi motors that do the same thing.
IMO, that’s not your problem.

I also agree with Andy on trying the single 4500 intake.

Very shortly after B1’s came out I dyno tested a 446 with a set that just got a mild bowl blend. It made just over 700hp, which seemed fantastic at the time.
In a 3000lb back half Cuda it went 9.40’s........this was in like 1991.

I rairly even bother checking exhaust flow numbers on my bench. My ears tell me more than flow numbers on exhaust side then I fine tune the air speed to get it where I want it.

Looking to send the heads out to someone who knows b1 originals for a second opinion. Then adjust my combo

Check this threadB1 heads
Do you check your pm's

Yes thanks for that

Lots of people have experience with B1 heads. My opinion for what it matters, just use someone who knows heads period. Guys who know how to make power will make it. With the stock block not sure I'd get to concerned with to much power. Sounds to me like you have some mismatched pieces. Id be looking at tuning the thing to try and find hidden potential, but in the end MPH tells the HP story. Me thinks you are well short of that HP number.

there is a fair bit wrong that engine should be close to 150 mph 9 flat just a comparison my sb at over 3550 lbs runs a 9.57@142 mph witch shows close to 800 hp ,get your box and converter checked for crazy slippage or something going on

For reference...... original B1’s prepped by Koffels.
Bowl and chamber work only:

28”, 4.375 bore, clay radius entry, no tube on ex:

Lift———in/ex
.100——78.9/58.5
.200——148.0/106.1
.300——216.0/146.4
.400——275.6/187.1
.500——326.1/219.2
.600——357.7/242.6
.700——378.4/257.7
.800——389.6/266.4

These made about 830hp on a 526 on our dyno with a single 1050 carb.

Dyno numbers aside, I think a cam swap and the single carb manifold would have improved the ET.

I was at the track a while back and a nice early B body with a Hemi and crossram was running 12's. So sometimes a combination just gets too complex and stops working right. When that happens you need to take it apart and work your way thru it. I highly doubt that the exhaust ports are the culprit but maybe that is the case. Send the heads to Fast and see what he says.

There are a lot of bad sheet metal intakes floating around. I've seen a few come across the dyno that wouldn't make squat for power. They look nice, but some guys building them focus more on the looks than how they work. It is the first thing I'd suspect when an engine isn't making good power.

I’ll be the first to admit that I haven’t really figured out how to get magic to happen on the flow bench with B1 heads.

I think I’ve only tested one set that had what I thought had really good exhaust flow..... and my recollection is they were huge(run on a 572 with spray).

This is more like what I see......
Some older bowl ported heads, mild “full” porting on the exhaust.

On the intakes I opened the bowls up and tweaked the short turns.
On the exhaust the primary thing I did was to narrow up the guide boss...... which was more work than it should have been for what I gained.

As rec’d:

Lift———in/ex
.100——75.6/53.6
.200——149.2/112.2
.300——220.8/165.9
.400——282.3/209.8
.500——336.6/236.2
.600——374.5/242.6
.700——371.7/241.9
.800——352.1/241.9

After rework:
Lift———in/ex
.100——73.7/54.2
.200——148.8/115.9
.300——219.6/165.9
.400——284.2/212.2
.500——338.4/245.7
.600——375.6/257.8
.700——408.0/258.9
.800——400.8/258.9

The thing with the ex flow is, you only need what you need, and blowing out the size of the port chasing a number on the flow bench isn’t likely going to get the car down the track quicker.

I guess the questions I’d ask are, what are the goals/expectations out of the build?
It would seem the OP must be pretty far off from where he wants to be if the motor was still running fine and he elected to remove it and pull it all apart rather than tweak on the combo in the car.

Just trying to eliminate one problem after another to gain more hp. There are quite a few combos out there similar to mine that make more hp.

If there are quite a few people running original B1 headed 451 type builds making more than 800hp, and running like 800hp should in a 3100lb car...... I think it would be in your best interest to chat a few of those folks up and see where they had their heads done.

Why try and reinvent the wheel?

BTW, did you discuss the performance(or lack of it) with Ray?
Did he offer any insight?

'shave run B1 stuff off and on for quite some time. For the performance you are getting from them I would say something is really wrong with the combination you have or the health of the engine in general. I personally would not build a 451 using them these days, but did back in the dark ages. Be interesting to see more info on the current combo, came compression etc.

Have you don e the basics? Leak it down, do a compression check, look at the plugs etc?

Al, he listed the combo:

Sure seems like one heck of an underperformer. Guess I missed that one.

I should have added check spring pressures as well to the list of places to start looking for missing HP...

The combo is a few pages back

AS I said I would start with basics of troubleshooting to see if there is an underlying issue causing the poor performance.

That’s what I’m going to do since it’s apart for it’s normal freshen up

Update. Sent the heads to CFE. Here is the email
Kevin,

there are some improvements to consider on the B1's. First would be from doing our valve job (which would add some much needed area under the exhaust valve), open up the bowls on the intake side to the common bolt hole (you would need to seal those bolt columns off with silicone during assembly), and straightening on some things in the chamber, particularly on the exhaust side. The chambers are all over the place in respect to transitioning to the bore diameter and some are opened up to 4.500" and over-hang the deck on your smaller bore diameter. Not the end of the world, but I thought I should mention it. As noted, we can straighten some of that out where there is material to work with. 

If interested, we could do our touches to them and the cost would be $1,800.00. The time frame would be two or three weeks at the most. If interested, and you'd like us to proceed, let me know and give me the specs on your current cam. I can give you some direction on what to do in that department.  

Let me know if you have some questions. We appreciate your interest. 

Scott @ CFE

WOW!!!!!!!! 1800.00 MORE.

That is the going rate to have any good shop hand work any head.

The question I’d be asking myself is, how much improvement(ET) would I have to see out of the $1800 head work for me to feel like I got what I paid for?

And then, is that expectation realistic for what they’re proposing?

I’d pay those guys to flow them as-is to see how well the numbers correlated to the numbers you already have before making any decisions about proceeding further.
My preference would be to flow them on as correct a bore size as they have, and with/without a correct sized flow tube.

What, exactly, does that $1800 get the OP? I saw reference to:
- valve & seat rework
- bowl enlarging
- some chamber work

Am I missing something else? Big-name shop or not, that seems like a lot of $$$ for just that amount of work.

PLEASE tell me I've misread what that quote includes...

I suspect they will be doing some repairs. Sounds like the chambers need some welding. Who knows what they need to do to fix the valve job.

I always charge more when I have to fix someone else's junk work. I especially hate trying to fix absurd valve jobs.

Sometimes, as I got older, I just turned some of the fix my junk [censored] away. Just wasn't worth the crap.

Darren at reher morrison quoted around 3500 to hand port a set, they dont have a cnc program for b1. I believe it was around 90 pesos an hour. The ideal person to get them to would be radar, if you can find him....

It all boils down to how much faith you have in XX shop. EVERYTHING has gone up in price EVERYTHING. Why not highly specialized shops with highly specialized skills with highly specialized equipment? I charge $105 CDN/hr and its barely enough, but you know what? People pay or they have to learn how to do it themselves--then they realize how cheap it was to send it to the machine shop in the first place. On the flip side of this coin are the idiot machine shops that still charge $100 bucks for a valve job or $75.00 for a line hone--they must like working at a loss. J.Rob

Jesse - No question that quality work with precision equipment justifies a fair & profitable price. However, this isn't the first time I've seen prices quoted/listed for specific jobs that were so much higher than what some other good shops charge that I suspect the difference was because of whose business name is on the top of the invoice.

Truer words have not been spoken.