Build Thread 1978 Mercury Cyclone. The pig is in the pen.

a91what said:

Sooo... gonna do one collector or make it so 3 pipes have a collector then each of those go into one? I know it's a bit late but won't a (merge?) header make better power?


Or did I miss the point and that's how your building this.

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I always intended to keep each bank merged separate, then merge both banks into one. It's gonna be cramped there as it usually is w/ any attempt to build an equal length shorty header.
As for whether or not it'll make more or less power or torque than some other version might have, that'll be a "never know",....I'm not building more than one of these replacement headers for this car.

Speaking of more or less power and torque.......

I did decide to cut the shafts on the Tb's so I can place them directly over the respective port. It's gonna be a needle in the haystack pain in the ass to do this......

The TB's all have to be precisely located so that they won't bind. Each TB has locating dowels built in that would have made it easy to remove and replace them on the engine they came off of just by popping the dowels into the holes in the head.. Those are dowel holes that I now have to drill in a piece of aluminum bar. Not only do I have to drill the holes for those dowels perfectly to ensure that all six TB's are not twisted and all at the right height to not cause shaft binding, They have to have my injector spacing now taken into account.

If I do my math correctly, and double/triple check myself, I may be able to do this right the first time...I'm thinking that a piece of aluminum bar 3/8-1/2" thick will be my mount flange...I'll lay out the spacing based on my 4.08" port spacing.
I'll have to drill (6) 1.625" holes that'll have to be made oval on one side of the plate to match the TB's mating surface, and blended like a funnel to the port opening. It's a good thing that the bases of those TB's are oval, because that'll guarantee that I get them all on the same plane simply by sitting them on a shoulder that I'll make from another piece of metal (like a framing square). That should guarantee that they are all not twisted, and at the same height. I can then center punch each TB's bolt hole pattern, and drill those 12 holes. then bolt them all on to determine what I'll do to reconnect the cut through shafts...(I just happen to have (6) 1/2" thin wall sleeves that I was gonna use as injector bosses...hopefully that shaft will be similar dimensions, and not hardened.
If the shaft is close enough to allow me to slide those sleeves over the cut ends of the shaft, I'll just drill a hole clean through the sleeve and shaft to let me bolt them back together...If not...I'll grind a "flat" on the shaft and use a set screw to do that.

Then if everything works the way I'm hoping it will,................I'll take those TB's apart, and have them PC'd (silver I think).
That is,.....if I can somehow have them keep the powder coating out of the throttle bore and the shaft bore.
Otherwise,...I'll clean them up best I can,...cut off what don't need to be on there,...and either paint or polish them myself.
I'll use the air injection boss as my vacuum port, I'll either fill those holes with epoxy, or pipe thread tap them for reducers that'll let me create the vacuum reservoir hard lines I talked about earlier.

I'll have to rig up a throttle linkage mount, and devise a way to hold on the fuel rail,..but those are incidentals...

I'm so looking forward to making this thing I can't stand it..