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Fast Flow Manifold, HD8's, BJ8 Cam, Will I Notice the Difference?

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cpcooper Craig Cooper
Chico, California, USA   USA
I'm midway through restoring my Mark I BN7 and dreaming about when I can begin working on things mechanical rather than things bodywork. Someone posted here about how gorgeous the "Fast Flow" aftermarket intake manifold available is and I tend to agree. Of course, this requires 2" carbs, a really nice set of which I recently purchased (Thanks Ian!). BUT... I've been looking at pictures of cars with the manifold and I'm not sure I want to deal with moving the carburetors that far out under the shroud and trying to figure out how to arrange air cleaners. So, now I'm thinking about hogging out my stock manifold to accommodate the 2 inch carbs. The other thing I'm considering is a BJ8 camshaft, presently available from BPNW for $560.15, no shipping, no tax.

So, the question is... Am I going to notice the difference with the larger carbs, more efficient manifold, better cam grind, and maybe some light porting and matching, or is it going to run about the same except for in high RPM's or some other seldom used range/condition? Or, am I actually going to lose some of the low end tractability I hold so dearly? This thing actually ran pretty well despite a 30 year hibernation and seemed turbine-like smooth in comparison to my love of my life BN1. Thanks for your thoughts and recommendations.

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HealeyRick Avatar
HealeyRick Rick N
MA, Northshore, USA   USA
I think you'll notice a difference, but your satisfaction is going to depend on your expectations. The BJ8 cam is still going to be plenty torquey and when you think of what you're proposing, you're basically going to end up with a slightly improved BJ8. When I first rebuilt my BJ7, it had triple HD8s, an Isky T3 cam, lightened flywheel and some light porting. It ran great, but just didn't seem to have the punch that I was hoping for. And that's how I ended up with a V8 Healey.



Rick

"Madman in a death machine"
Austin-Healey 3000 w/5.0L and T5Z: http://forum.britishv8.org/read.php?13,8264

Dougie Avatar
Dougie Doug Escriva
Portland, Oregon, USA   USA
Make the improvements and get a lightened flywheel. You'll feel the different and like it.....

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sliproc Avatar
sliproc Kevin Quistberg E
Long Beach, california, USA   USA
Craig,

You're asking an age old question, will I notice the difference? Answer, probably yes. But maybe the question you should be asking is do I want a fast car or do I want a fast Healey? You got two interesting answers; Rick, wanted a faster car, hence the V8, Doug, races his so he needs a faster Healey.

It's also a question of bang for your buck. You can spend a lot of time and money modifying your Healey and get a modest performance improvement or you can go off the grid for the same money and come up with something really wild(see Rick).

Your car, your choice.

cpcooper Craig Cooper
Chico, California, USA   USA
Good points... Fast Healey, I think. I've had a lot of different Healeys over the years, 4's, 6's, and, yes, a couple of V8 cars. If installing an other than stock engine and trans didn't about halve the value of the car, I'd be out in the shop right now dropping a Honda VTEC S2000 motor into my BN1. 240ish horsepower, revs to 9K, 6 speed trans, probably 250 pounds lighter than the A90 and 3 speed OD, what's not to like? As for the BN7, there are some nice 6 cylinder Japanese engines available, and scads of inexpensive and powerful US V8's. For my tastes though, at least a little bit nostalgic, a mildly breathed on Healey 6 is going to work out fine. I ordered the BJ8 cam yesterday, and already have the HD8 carburetors, so I guess the question at this point is whether the trick manifold would make an appreciable difference. Anyone have before and after impressions using one?

HealeyRick Avatar
HealeyRick Rick N
MA, Northshore, USA   USA
In reply to # 195632 by cpcooper If installing an other than stock engine and trans didn't about halve the value of the car, I'd be out in the shop right now ...

Half the value, but double the fun. the finger smiley



Rick

"Madman in a death machine"
Austin-Healey 3000 w/5.0L and T5Z: http://forum.britishv8.org/read.php?13,8264

cpcooper Craig Cooper
Chico, California, USA   USA
Good point! Also, since I seldom sell my cars, it doesn't matter what they are "worth". Frankly, I'm getting a little tired of skyrocketing vintage car prices and the crowd they attract. Liked it better when I could find a derelict BN2 in someone's driveway, buy it for a few hundred, fix it up and sell it for probably three hundred less than I was in it.

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DerekJ Avatar
DerekJ Derek Job
Cotswolds, Gloucestershire, UK   GBR
The fast flow manifold will of course help but given that you are just going with a BJ8 cam then its probably not worth the extra money. The biggest performance improvement comes with an uprated cam. The DWR8 fast road cam is an excellent compromise but does need pockets in the block. You should also consider the fast flow exhaust manifolds (headers). They are good for about 5-8bhp. They do change the sound of the Healey though.



Derek
www.healeysix.net

petnatcar Avatar
petnatcar Silver Member Peter Carbone
Watertown, New York, USA   USA
Hi Craig,

I have one of the RAWLES Intake Manifolds and there is a noticeable difference in performance.

Compare the OEM manifold with the RAWLES manifold and try to convince me that the RAWLES wouldn't be a better performance option. Just look at how smooth the runners are. They blast the air right into the cylinders with out having to make so many right turns that slow down the speed of the charge.
I'm surprised the engines ever ran properly with all the square corners on that manifold.

Maybe that's why they went to 3 carbs for the rally cars? Better breathing.

It's not such a big deal with the air cleaners.
I think K&N has some cool pancake style ones and there are a few others out there that have a shaped backing plate
that mimics a velocity stack, thus increasing the speed of the air. http://www.hi-flow.com/HP007aAF.html

I run velocity stacks with stainless mesh screens mated to a cold air intake from a scoop behind the grill.
There's nothing like cool air to make the engine run better.

You need to remove the dashpots to install the carbs on the RAWLES intake but it's no big deal.

The addition of the HD8 carbs is a good performance improvement.
I've had them mine on my engine since 2000 and they still run perfectly.

I also have one of the DWR8 cams but I'm gonna replace it with a stock BJ8.
Those were the cams the factory used in the race cars so that'll be good enough for me.

For some reason my engine runs out of breath at 4500-5000 rpm with the DWR8 cam.
But I was able to hit 6000 with the BJ8 cam.... go figure...
I thought the DWR8 would be better but it wasn't that good for me.

You can't go wrong with tubular headers. They're good for at least 10% more power.
Don't waste the money on stainless steel but rather have the regular steel headers coated with the JET HOT coating.
It improves the flow and keeps the temperature down a little.

I can go 110 mph on some of the back roads around here and that scares the liven' crap out of me but
I can't wait to get out there and do it again tomorrow.

You may want to work the suspension over if you like to drive fast and get some good tires.

I don't race my car but since making so many improvements I can now drive it like a race car.

Good luck,
Peter

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