1935 Chevy Master 409 Stroker Project

Jim409_Pontiac

Well Known Member
Supporting Member 2
#21
You are running almost the same HP and weight as my 61 poncho and it has run a best time of 10.37, so if you can hook you are going to need the roll bar. Other safety gear too. The car sounds awesome.
 

jim_ss409

Well Known Member
Supporting Member 5
#22
That car is definitely going to be quick! :beer

Here's a link to an interesting article about camshafts...
http://www.popularhotrodding.com/tech/0607phr_camshaft_basics/viewall.html
If you look at this chart from the article you can see that your 85 degrees of overlap puts you into the top of the "street strip" range or the bottom of the "race" range.
Street / strip is 4 on the chart, race is 5


It is a big engine and the car is light so it's going to be fine but it will have a lumpy idle unless you rev it up a bit.
By the way, you can often gain a bit of top end power by adding an open carb spacer but it will make the engine idle rougher and reduce the off idle throttle response, so I don't think it would be a good idea on an engine like yours.

I'll run your specs through a header design program tonight when I get home but I'm guessing it's going to suggest about 1 7/8" to 2" for the primary pipes.
 

jim_ss409

Well Known Member
Supporting Member 5
#26
I ran your specs through my header program.
For street use it recommends an outside diameter of 1.843 or about 1 7/8" and a length of 34.1 to 36.9 for the primaries.
It also recommends a 3.375" collector with a length of 19" (3 1/4" would probably be the closest but either 3" or 3.5" should be fine)

For race use it recommends an outside diameter of 1.846 to 1.971 so about 1 7/8" to 2" and a primary length of 34.1 to 36.9 (same primary length as the street headers)
It recommends a collector outside diameter of 3.375 to 3.625 with a length of 19"

They say not to loose too much sleep over getting the primary lengths right but it is nice to have a number to aim for.
Apparently the collector length is the most important thing to get right. If you're running full exhaust it won't matter but if you are building headers that can be uncorked aim for a collector length of 19"
If you're putting in a crossover or cut outs, putting them in at 19" will give you the best results.
 
#27
Jim,
We're going to dyno test my intake manifold pretty soon. I have two very different sets of headers that I can use.
A set of the old Belanger design, which are 1 7/8" tube, 36" average length, and I have collector extensions that make the 3" collector about 18" long.
I also have my ridiculous large tube headers from my race car... 2" stepped to 2 1/8", avg 35" length, 3 1/2" collector, which I can extend to 20".
The cam is not crazy, and it IS a small port engine. Just for fun though, I think when my intake is on, and we've finalized the tune... it might be an idea to see what the too-big tubes do:rub
 
#28
I ran your specs through my header program.
For street use it recommends an outside diameter of 1.843 or about 1 7/8" and a length of 34.1 to 36.9 for the primaries.
It also recommends a 3.375" collector with a length of 19" (3 1/4" would probably be the closest but either 3" or 3.5" should be fine)

For race use it recommends an outside diameter of 1.846 to 1.971 so about 1 7/8" to 2" and a primary length of 34.1 to 36.9 (same primary length as the street headers)
It recommends a collector outside diameter of 3.375 to 3.625 with a length of 19"

They say not to loose too much sleep over getting the primary lengths right but it is nice to have a number to aim for.
Apparently the collector length is the most important thing to get right. If you're running full exhaust it won't matter but if you are building headers that can be uncorked aim for a collector length of 19"
If you're putting in a crossover or cut outs, putting them in at 19" will give you the best results.
Thanks for doing that! I'll discuss this with Sandersons when I bring the car over.
 
#30
I just went out there with a tape measure, there's just not enough room there to put tubes that long on my car, so I'll get whatever they can fit at this point. :rub
 

jim_ss409

Well Known Member
Supporting Member 5
#31
My header program also suggests tube length for mid length headers.
It says 23.8" to 26.6" is also a tuned length.
You're not going to be short of power no matter what you do so I wouldn't worry too much about the primary lengths.
 

Iowa 409 Guy

Well Seasoned Member
Supporting Member 10
#32
You will absolutely love thast HR636.:dance If you have a stroker, idle will be no problem. Idle at 1000 to 1100 no need...........600 will be smo0th. ............
OK.......i lied.........at least my memory did.:dunnoWent out and started the "64" and let her warm up. It is idling at 850RPM according to the tach with the mufflers on. Probably could go down another 100 rpm, but not any lower, never get down to 600. Your motor combo will be very streetable. Sorry for the mis-information. Might have killed to many brain cells eariler in life... :cheers
 
#33
OK.......i lied.........at least my memory did.:dunnoWent out and started the "64" and let her warm up. It is idling at 850RPM according to the tach with the mufflers on. Probably could go down another 100 rpm, but not any lower, never get down to 600. Sorry for the mis-information. Might have killed to many brain cells eariler in life... :cheers
I can relate to that! :cool:
 
#35
Passengers side during installation.
DSC00124r.jpg

Drivers side.
DSC00130r.jpg

Ready to start!
DSC00169r.jpg

After the first trip!
IMG_20130423_131750_098r.jpg

It runs great! there was only one problem, I used Dynomax VT mufflers, they have a spring loaded valve that's supposed to cut down the noise and reverberation at low speeds and open for full flow at higher rpms, sounded like a good idea but they rattle constantly and loudly in my car, so they've got to go! I'll post a link to a video after I get that little problem fixed.
 
#38
Yes, and Magnaflows will going into mine as soon as I can get it into Sandersons, which might not be till the beginning of June. They do good work so they're always booked up. I bought the mufflers so that was my fault...:doh
 
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