460 swap into a 78 Bronco

[ArdWrknTrk]

Good point!! Dang it... I could have sourced the 45 degree elbows locally without those crinkles (only used 1), but not the 20 degree elbows (used 4).

I hadn't thought of these crinkle bends being more rust prone as they are (thinner or because they trap salt?)

But reading about them just now, supposedly they can increase backpressure some which in my case might be helpful, supposedly EGR needs some backpressure to have sufficient exhaust pressure available (even though vacuum is what is pulling it) ?

I think Walker crinkles the already aluminized tube.

Certainly the compression in those bends changes the structure, because they are not normalized (annealed) after bending.

There's always going to be some pressure for EGR (unless your truck has zoomed, like a top fuel dragster....

8th bends are pretty common.

Even 16th bends aren't too hard to find.

I've never seen 18th bends off the shelf.

You usually have to pie slice those from a U-bend or something..

[viven44]

I think Walker crinkles the already aluminized tube.

Certainly the compression in those bends changes the structure, because they are not normalized (annealed) after bending.

There's always going to be some pressure for EGR (unless your truck has zoomed, like a top fuel dragster....

8th bends are pretty common.

Even 16th bends aren't too hard to find.

I've never seen 18th bends off the shelf.

You usually have to pie slice those from a U-bend or something..

On the 18th bend i.e. 20 degree elbow you are correct, did not find one immediately on the shelf but OReilly overnighted me about 4 elbows for a store pickup

I found 2 sources of those bends

Amazon -- Walker Exhaust 41818

Oreilly - Nickson 20 Degree Exhaust Elbow | NIC 548775

[viven44]

On the 18th bend i.e. 20 degree elbow you are correct, did not find one immediately on the shelf but OReilly overnighted me about 4 elbows for a store pickup

I found 2 sources of those bends

Amazon -- Walker Exhaust 41818

Oreilly - Nickson 20 Degree Exhaust Elbow | NIC 548775

Took advantage of some time on hand at Spring Break. Pushed to get the Bronco project to a halting point. I wanted to get some running action, with forward and backward movement to get the fluids going so I can rest for a bit.

The only issue was the throttle rod on the 78 bronco was too short, it was a threaded rod, but siezed up hard and it broke. I have a replacement arriving for a late 60s mustang that also has a bend to help clear the carburetor, lets see if that works.

But that didn't stop me. Some "brown-neck" engineering with a "throttle cable" for now.

With all the fluids in, I fired up the 460. No hesitation, started right up like it's been in there always. There was probably a exhaust leak when cold that I need to sort out but after things warmed up it sounded wonderful.

I got the timing just right on the first go luckily (~8BTC). Oil pressure ~70PSI warm and over ~40PSI cold. On the Bullnose truck, the numbers were ~60PSI warm and about ~30PSI cold. The only change was deleting the oil cooler. Different oil pressure gauges were used however, so that might be a factor as well.

The alternator was not charging, did a parts swap with another voltage regulator. The terminals were just corroded and probably not getting field voltage, I could have cleaned them up, but hey at the heat of the moment the swap did the trick.

My only disappointment with the exhaust job is that the "universal" tail pipe won't fit right, its too close to the axle. I decided to just install it as-is for now because raising it would cause it to hit the fuel tank, but I'll need to do some modifications later.

I have established it moves forward and backward. Initially there was hesitation to switch between gears but I was ~2.5 quarts low on fluid. That took care of that.

Oh and we have a little over 20" vacuum, not enough to leak through the distributor unfortunately . I retorqued all the intake bolts, except a couple which are not reachable. All the others didn't need any torque adjustment and held the torque so i'm hoping its all good.

[Gary Lewis]

Took advantage of some time on hand at Spring Break. Pushed to get the Bronco project to a halting point. I wanted to get some running action, with forward and backward movement to get the fluids going so I can rest for a bit.

The only issue was the throttle rod on the 78 bronco was too short, it was a threaded rod, but siezed up hard and it broke. I have a replacement arriving for a late 60s mustang that also has a bend to help clear the carburetor, lets see if that works.

But that didn't stop me. Some "brown-neck" engineering with a "throttle cable" for now.

With all the fluids in, I fired up the 460. No hesitation, started right up like it's been in there always. There was probably a exhaust leak when cold that I need to sort out but after things warmed up it sounded wonderful.

I got the timing just right on the first go luckily (~8BTC). Oil pressure ~70PSI warm and over ~40PSI cold. On the Bullnose truck, the numbers were ~60PSI warm and about ~30PSI cold. The only change was deleting the oil cooler. Different oil pressure gauges were used however, so that might be a factor as well.

The alternator was not charging, did a parts swap with another voltage regulator. The terminals were just corroded and probably not getting field voltage, I could have cleaned them up, but hey at the heat of the moment the swap did the trick.

My only disappointment with the exhaust job is that the "universal" tail pipe won't fit right, its too close to the axle. I decided to just install it as-is for now because raising it would cause it to hit the fuel tank, but I'll need to do some modifications later.

I have established it moves forward and backward. Initially there was hesitation to switch between gears but I was ~2.5 quarts low on fluid. That took care of that.

Oh and we have a little over 20" vacuum, not enough to leak through the distributor unfortunately . I retorqued all the intake bolts, except a couple which are not reachable. All the others didn't need any torque adjustment and held the torque so i'm hoping its all good.

Congratulations!!! Such a good feeling.

There are always the little details to work out, so the exhaust issue is to be expected.

Shame about the lack of a vacuum leak. What are you going to do?

[viven44]

Congratulations!!! Such a good feeling.

There are always the little details to work out, so the exhaust issue is to be expected.

Shame about the lack of a vacuum leak. What are you going to do?

Thank you. Yes it is a nice feeling indeed. Now I can rest knowing all the good oils have circulated inside a little bit.

Since the vacuum is nice and relatively steady even when cold, I have the distributor hooked up straight to manifold vacuum for now, until VREST, EGR etc is all ready

 

[viven44]

Congratulations!!! Such a good feeling.

There are always the little details to work out, so the exhaust issue is to be expected.

Shame about the lack of a vacuum leak. What are you going to do?

The other option on the tail pipe is to use a Bronco 2 1/4 tail pipe. That would fix this issue instantly.

If I went from a 3" tail pipe to a 2.25", would that hurt anything ? All lines from manifold, up until the muffler are 2.5"

[Gary Lewis]

The other option on the tail pipe is to use a Bronco 2 1/4 tail pipe. That would fix this issue instantly.

If I went from a 3" tail pipe to a 2.25", would that hurt anything ? All lines from manifold, up until the muffler are 2.5"

Not sure I understand. You have dual 2.5" pipes to the muffler and a single 3" out? If so I don't think I'd go down to 2 1/4". I'd go to a muffler shop and have them graft on either a 3" or at least a 2 1/2".

[ArdWrknTrk]

The other option on the tail pipe is to use a Bronco 2 1/4 tail pipe. That would fix this issue instantly.

If I went from a 3" tail pipe to a 2.25", would that hurt anything ? All lines from manifold, up until the muffler are 2.5"

2.25" out is not nearly enough for a 460.

You really ought to consider a 3G swap.

Even a 95 amp unit will charge much better at low engine RPM then a 1G could ever consider.

[viven44]

2.25" out is not nearly enough for a 460.

You really ought to consider a 3G swap.

Even a 95 amp unit will charge much better at low engine RPM then a 1G could ever consider.

OK thanks Gentlemen! I'll modify the current 3" tailpipe to make it work. Its just that I'm out of breath on exhaust so thinking of all the short cuts!

I was really thinking in my head on how the restrictions may be more critical the closer to the engine exhaust manifold, and towards the tail of it, it may not make much a difference but for appearance alone I think a 3" would be preferred.

And Jim, I'll probably switch out to a 95amp unit next time I order something from Rockauto.

[ArdWrknTrk]

OK thanks Gentlemen! I'll modify the current 3" tailpipe to make it work. Its just that I'm out of breath on exhaust so thinking of all the short cuts!

I was really thinking in my head on how the restrictions may be more critical the closer to the engine exhaust manifold, and towards the tail of it, it may not make much a difference but for appearance alone I think a 3" would be preferred.

And Jim, I'll probably switch out to a 95amp unit next time I order something from Rockauto.

DO IT!

You won't be disappointed.

I order from DB Electrical.

But, you be you....