Dyno results for 3353

[PhilS]

I finally got the engine to Stanley's for dyno work. We ran it with factory log style manifolds, water pump and alternator. I don't know how much power we lost but I wanted to know what I will actually have in the car. Small Comp Cams solid roller was the biggest difference from stock. Dove roller rocker set up and single carb on a sidewinder. Max power of 430.5 @ 6100 and torque of 415 @ 4900. Those manifolds just wouldn't let a lot of exhaust out.

[shelbydoug]

Back in the day that was OH WOW! power.

[GT350Lad]

Back in the day that was OH WOW! power.

Still pretty impressive, well done 👍

[CSX 4133]

Still that's very decent power, especially when considering the power to weight ratio.

[shelbydoug]

This cam?

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=951&sb=2

These things need very low restriction on the exhaust system to work. That's why it says, "must use headers". It is a 110 centerline.

ANY exhaust restriction just turns it off.

100hp bottled up is probably a conservative estimate? '70s testing methods were showing as much as a 150hp gain with headers and side pipes but you could go under now with as little restriction AND use a balance tube which definitely helps smooth out the idle.

It also will stop what mimics the sound of an engine misfiring caused by the lack of a balance tube.
It isn't misfiring, just has an unbalanced firing order with two separate banks of exhausts.

[PhilS]

Good info, thanks. It is the same cam. When I called CC they didn't mention the need for headers but I knew the stock manifolds were bad anyway. I'm considering headers now but want to be as stock as possible. Nick Acton has a set similar to the ones Shelby had made. Be nice to let it breathe. Its scfm at 6500 was only 651.

[shelbydoug]

Phil, I'm not personally versed in how to put headers on a 427 Cobra. In my day they needed to be built on the car.

I remember CSX3121 going that route.


Check with Curt Voght at Cobra Automotive. I think he has done more then one set. I know that he has a header builder, computer and all, calculates everything, that can build them for you. Pricey though.

When you see what he has had there in the shop and probably what he has in the shop currently you won't feel uncomfortable about leaving the car out of your sight. Usually a bunch of GT40's, R's and T/A cars. It's a sight to behold.

It's a lot like the 'Race Shop' at SA back in the day.



I've become a big fan of a completely stock looking street 427. It must be a mature acquired taste? They have great subtle lines. I'm over the S/C thing.



I've also learned to weld on the cast iron exhaust manifolds with stainless rods. I'm wondering if 428cj cast manifolds could fit over the chassis tubes with a little welding, etc?

Lot's of folks have been sneaking them on GT500's that never had them before. Cobra Automotive has been extrude honing manifolds and I think that some of the cast aluminum "cheater" sets might still be around.

They aren't as good as headers but they do help and they sure are much quieter. Kind of fit into the "stock car" thing you have going on maybe?


Shouldn't that car have been built with a '67 2x4 Holley intake?

[PhilS]

I will probably stay original but the thought of another 100+ hp is appealing.
The '67 Cobras were different. Someone correct me if I'm wrong. Street cars by the year; '65 427 low riser, center oiler 8v...'66 428 pi 4v...'67 427 medium riser, side oiler 4v with sidewinder intake. A few exceptions.

[shelbydoug]

I will probably stay original but the thought of another 100+ hp is appealing.
The '67 Cobras were different. Someone correct me if I'm wrong. Street cars by the year; '65 427 low riser, center oiler 8v...'66 428 pi 4v...'67 427 medium riser, side oiler 4v with sidewinder intake. A few exceptions.

Not to be critical but that cam is hardly original and has somewhat of a radical idle. 

I have seen installed in Cobras this cam.

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=947&sb=2

Probably not much difference between the two but simpler to maintain.

In other words, it will stick out not like a sore thumb but more like a marching band. Boom, boom, bad-bad boom!

[CSX 3183]

The 65 AND 66 street  427 Cobra was a center oiler, and low riser, with 2 x 4's, , up until CSX 3200, that is when they became 428's with a single 4, at CSX 3300, they again were 427's, now med riser, with a single 4, the 3200 and 3300 are approximate change, it might be 3201, can't remember exactly, too much chemo, now have chemo brain, sometimes I remember, sometimes I don't.

I will probably stay original but the thought of another 100+ hp is appealing.
The '67 Cobras were different. Someone correct me if I'm wrong. Street cars by the year; '65 427 low riser, center oiler 8v...'66 428 pi 4v...'67 427 medium riser, side oiler 4v with sidewinder intake. A few exceptions.

[Dan Case]

There were "factory" under car headers for 427 Cobras but apparently not very popular. They had four each two pipe Y sections that bolted to down pipes conceptually like very early (few few cars) CSX20xx cars with tubular steel exhaust.  All bolted up they were sort of tri-y style. CSX3141 was equipped with a set.

[Cobra Ned]

"I've become a big fan of a completely stock looking street 427. It must be a mature acquired taste? They have great subtle lines. I'm over the S/C thing."



Ha. One of the reasons I sold CSX 3042 after 20 years. But I sometimes wonder if it's more of an age thing...

[shelbydoug]

"I've become a big fan of a completely stock looking street 427. It must be a mature acquired taste? They have great subtle lines. I'm over the S/C thing."

Ha. One of the reasons I sold CSX 3042 after 20 years. But I sometimes wonder if it's more of an age thing...

The term "boy racer" comes to mind.

It is somewhat surprising to me to see how many street cars survived without being "S/C-ized".

The main contention against the street cars seems to be the huge rear fenders vs. the Sunburst wheels? 10" wide rims seem to fit so well by comparison.

I think the effect of age would be more that you want to drive your Mercedes-Benz instead of any kind of an open car. Maybe concern that the wind will blow off your toupee?