Thoughts on my planned combo

[ToddK]

I'm gathering parts together to build a new engine for my recently acquired 63 Galaxie boxtop. It currently is a Z code 4speed and I would like to build it into a G code clone. The car will be 98% street driven, with a very occasional 1/4 mile run. I want it to look very factory stock externally and under hood, though it won't be a total matching numbers type clone. Here's the engine combo I currently have parts for:

Genesis cast iron block 4.28" bore
Steel 4.25" stroke crank
Diamond flat top pistons - should produce 10.5 to 1 comp
Pond MR heads, stock ports, flowed 305 at 0.600", 315 at 0.700"
Tripower intake system
427 cast exhaust headers
Factory dual point distributor with Duraspark conversion, MSD 6AL.

I plan on using a Hyd roller cam, something around the 245 at 0.050" duration. I think that with this many cubes and only a tripower feeding it, peak hp will be limited to around 5500rpm, so I will cam it accordingly. Plus, I will keep the stock 3.5 diff gears and be looking for big  torque to keep the big car lively on the street. I don't want a wild idle, but something that sounds nice and won't be a pain to cruise with. Any thoughts or suggestions for the cam?

Also, I realise that there is a port mismatch between the Pond MR heads and the tripower intake. I went with the Pond heads because externally they look very similar to factory iron heads and with a coat of black paint they will look the part. Is it worth trying to weld the bottom of the port floor on my tripower intake to build a smoother transition, or at these rpm's and power levels is it not worth the effort? I'm hoping to achieve 500+ hp and 550+ ft.lbs of torque. Is this realistic?

Any thoughts or suggestions on this combo would be appreciated. Thanks.

[machoneman]

Perhaps Jay can comment on the tri-power intakes limits but it's the cork in the bottle, for sure.  Hate to see all those great parts hp limited by the alleged cool factor of three deuces but hey, go for it.

[ToddK]

Yes, I realise the tripower will be the cork in the combo, but I do love the look of them. If it gets all too much of a power strangler, I can easily get my hands on a MR port tunnel wedge. But I'm not going for ultimate hp, I want a nice street cruiser that will go hard when the pedal is pressed.

[jayb]

One of the rather interesting things I found during the testing for my book was that at least up to 500 HP or so, the medium riser to low riser port mismatch didn't seem to make any significant difference in horsepower.  I tried the combination both ways, with a low riser manifold port and a medium riser head port, and also a low riser head port and medium riser manifold port.  These mismatches just didn't make a difference.

Probably one reason is that the port flow tends to follow the roof of the port.  As the port bends down to aim the a/f charge at the valve, the flow wants to stay along the roof, so what happens along the floor of the port is much less important.  You'd think that a mismatch of .300" or so at the floor of the port would really disturb the flow, and maybe it does, but it didn't make a difference in torque or power production.  

I would for sure concentrate on a good match between the manifold and head port on the roof and sides of the port, but the floor is much less important.  I think I saw your pics on the FE Forum, and I guess the only thing I'd be concerned about is the uneven surface of the floor as a result of the welding.  You may have done more harm than good there.  I'd either grind the welds out of there and go back to the factory low rise port height, or else get them welded farther in to the port so you can keep the port floor smooth.  And definitely widen the manifold ports to match up to the width of the head ports if necessary.

I would be cautious about filling that area with epoxy, by the way.  Unless the surface is scrupulously clean and rough enough for the epoxy to grab, you might be asking for trouble there.  The intake port can be a violent place, and even in a good epoxy installation any epoxy layer thicker than an eighth inch or so is liable to eventually crack and break off, in my opinion.

I also agree with Bob that the tripower is a definite cork in your combination, but hey, it sure looks cool, and it won't hurt you too badly at the lower speed ranges.  Your cam choice might actually be a little strong for that manifold, but I'm sure it will work OK.  You will have quite the stump puller there...

[BarryB]

Something else that can be done is to use the bigger Holley two barrel carbs on the ends. You would have to get the holes enlarged but it apparently works quite well and was done back in the day. I have a tri-power intake as well that I am doing this to. Kinda one them whenever-I-get-to-it deals, the carbs are machined just not assembled.

[ToddK]

Actually, the thread over on the FE forum is not my build, but it was what inspired me to ask these questions. From what I read on that thread, and backed up by what Jay has found, I don't think I will bother trying to weld the port floor of my intake, but just concentrate on matching the port sides and roof.

I initially plan on using the factory sized carbs and will see how it runs. I might try and get a pair of bigger carb bodies to try on the outer positions.

As far as the cam goes, I figure with 489 cubes it could handle a duration in the 240-245 range and still be well behaved at low rpm. I guess I am just after any advice as to how well it would work wth the overall combo. When it comes time to buy the cam I will get a custom grind. But at this stage I'd just like an idea of what would work best.

[plovett]

I would suggest the Medium Riser 2x4 bbl dual plane intake, either the Ford or Blue Thunder versions. 

That should supply the multi-carb visual appeal, but with much better performance than a 3x2 bbl intake.   And I imagine it would have better low speed manners than a Tunnel Wedge.  I think the Medium Riser 2x4bbl intake fits for your combination perfectly.

JMO,

paulie

[Glenn N]

What about one of those 3x2 tunnelwedge intakes Carls sells? Might improve things over the stock 3x2 intake? Won't have much of the stock 406 look though. BTW I really like those Pond MR heads too. I have been tempted to sell my tunnelport stuff and try a pair with a MR 2x4.

www.carlsfordparts.com

[ToddK]

I've seen those tunnel wedge 3x2 intakes, I'm sure it would perform better than the factory. However, I do really want a factory appearing engine. I love the whole sleeper idea.

When I originally started planning for the engine, I was going to use the Blue Thunder MR 2x4 intake and a pair of Barry R's carbs. However, I wanted to be a bit different and build a G code clone, as opposed to an R code clone. And seeing as my car is a boxtop, a G code engine would suit it better, IMO. But in time I can always buy the 2x4 intake set up and change the fender badges.

[Glenn N]

Yep I can understand wanting it to look factory. I like the sleeper look too. No idea how those 3x2 TW's run but they sure look interesting. 

[plovett]

I recommend getting Jay's book if you haven't.  I was surprised at how well the Blue Thunder 2x4 bbl did on a wide variety of engines, from mild to wild.  Fantastic manifold in my opinion.  Before reading Jay's book I bought a Tunnel Wedge intake to replace the Blue Thunder 1x4 bbl intake I have now, but after reading the book I would have considered the BT 2x4 instead.  It did great even without any portwork.

What I'm getting at, even though you stated this engine is primarily for cruising; I think you will be giving up a large amount of power with the 3x2 bbl intake vs. a good 2x4 bbl intake.    If you're okay with that then it sounds like your decision is made.

JMO,

paulie

[plovett]

Hey Jay, do you mind if I post the numbers out of your book comparing these two intakes on your 390 stroker motor?

paulie

[jayb]

Not at all, go ahead.  Posting the numbers isn't any kind of copyright infringement, which is the only thing I'm really concerned about.  Just don't post copies of the pages or graphs or anything like that.

[plovett]

Okay, here's real world numbers from Jay's book.  These are from the 390 Stroker motor which is closest in hp to Todd's motor's goals (500hp).

Peak HP:

     Ford Tripower 3x2bbl (port matched):  477.4 hp at 5800 rpm
     Blue Thunder 2x4bbl (unported):  517.7 hp at 5700 rpm

Average HP (3000-6000 rpm):

     Ford Tripower 3x2bbl (port matched):  398.7 hp
     Blue Thunder 2x4bbl (unported):  419.2 hp

Over 40 peak hp and over 20 average hp is bunch in my book, especially since the BT 2x4bbl provides a factory mult-carb look.  The BT intake really starts to pull away from the Ford Tripower at around 4200 rpm so it's not as if it's power increase is only at high rpm.   

paulie

[ToddK]

Well, after much thought, I have decided to bite the bullet and have ordered a new BT MR 2x4 manifold and a pair of Barry R's custom carbs. This will work much better with the heads and cubes I have, as has been proved by both Jay and others. And I will probably swap the tripower onto a 390 I also have, it should work better on an engine that sized.