My 1st. Street 383 Build

Thinking ahead about headers, clearance, spark plugs and all that fun stuff specifically related to C3 Corvettes. Looking for feedback from those who have gone through this before.

So here’s the setup.
1978 Corvette
Gen1 350/(383)
Dart SHP 200cc aluminum heads
Straight plugs
Manual Trans
Power steering
no AC
no emissions

Looking at Hedman 68306 headers. Need to call Hedman and ask about the “Will not fit with steering damper inside front crossmember” and to get their recommendations.

Install question:
- Install the headers on the engine while on the stand then install with the engine.

- Drop the headers in the engine bay before putting in the motor. Tie them out of the way and then install after motor is in.

- Install the engine without the headers then install the passenger side header from the top and drivers side from the bottom.

Spark plug questions:
- Are shorty plugs a requirement with these headers or will I have to wait and see after I get it all assembled?

- Does a gasket seal, 14mm, .750 reach shorty plug exist other than the Accel 0414S
 
I don,t remember using headman small block headers on a c3 corvette, I usually use hooker headers, on SBC c3 corvettes, but Ive never installed headers without the engine already in place in a c3 corvette, and Ive never had any difficulty doing it that way.
 
grumpyvette said:
I don,t remember using headman small block headers on a c3 corvette,
Click to expand...

Yep, your right, heard back from headman and they don't have one that will fit my combo.

Still on the header discussion. I have noticed some of the Hooker headers have 'oval' ports. Like 2456-1HKR. Does this mean they will not work with 'square' exhaust ports on the heads?
 
bytor said:
grumpyvette said:
I don,t remember using headman small block headers on a c3 corvette,
Click to expand...

Yep, your right, heard back from headman and they don't have one that will fit my combo.

Still on the header discussion. I have noticed some of the Hooker headers have 'oval' ports. Like 2456-1HKR. Does this mean they will not work with 'square' exhaust ports on the heads?
Click to expand...

NO! the shape change won,t hurt, in fact the slight miss match leaves a small ledge that beneficial, as it tends to slightly reduce reversion pulse strength, thus helping cylinder fill efficiency
 
Had a few follow up discussions with Holley regarding header recommendations and fitment. Looks like the 2134-1HKR and the 2456-1HKR are options. The expensive one being 1 3/4 diameter primary tubes ‘tuned’ vs. the budget minded 1 5/8 diameter tubes and not tuned. Holley recommended the 1 3/4 2134-1HKR what the right choice for my build so that’s the direction I’m leaning. I was originally leaning towards the 1 5/8 tube headers not wanting to affect bottom end torque but after doing some research looks like I won’t realize that much of a difference regarding torque. We are only talking about 1/8 difference and 500RPM. So, I think going with their recommendation is a sound one.

A few progress pics. Got the oil pan installed with no issues and did some starter test fitting.
 

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I have no idea why it didn,t show until I went back to look after your post, I must have done something wrong posted that
 
Flywheel question but I think I know the answer.
I'm running an internally balanced rotating assembly with a neutral balanced flywheel. The lack of the flywheel/crankshaft dowel is not a concern because it's used to index a external balanced setup correct?
 

Are you saying there is no hole for a dowel in the crankshaft ? I'm not sure if there
is a concern, but it would provide additional support for the shear stresses that are
placed on the flywheel bolts.

 
Indycars said:

Are you saying there is no hole for a dowel in the crankshaft ? I'm not sure if there
is a concern, but it would provide additional support for the shear stresses that are
placed on the flywheel bolts.
Click to expand...

There's a hole for the dowel, I just don't have a dowel. All the reading I have done it looks like the dowel is just for indexing a balanced flywheel to the crank. In my case, I'm internally balanced. I believe using the correct ARP flywheel bolts with shoulders, the dowel is not required. I'll get some pics up of the crank and flywheel.

I'm taking a break from the build because I have a busy October. Lots of Florida Gator Football to watch on Saturdays! Bell housing, clutch, EFI and yanking the old engine are on the to-do list for November.
 
bytor said:
Flywheel question but I think I know the answer.
I'm running an internally balanced rotating assembly with a neutral balanced flywheel. The lack of the flywheel/crankshaft dowel is not a concern because it's used to index a external balanced setup correct?
Click to expand...

yes thats basically correct the dowel pins main function is mostly to mandate only a single location for the flex plate or flywheel can be used to mount the parts insuring the proper balance is maintained because the parts MUST be assembled so the index pin dowel sticks thru the locating hole, in most cases the pin doesn,t even firmly contact the walls of the hole in the in the hole in the flex plate or flywheel.
on many chevys its a SPLIT pin dowel thats used to precisely locate the flywheel, on older engines, it was a press fit .
while it certainly doesn,t hurt to have it installed its not a 100% mandatory thing PROVIDED the flex plate or flywheel is indexed so it could be in its designed location.
flypin.jpg


GM
350 CRANKSHAFT TO
FLYWHEEL
SPLIT PIN
.437 x .500
87-97

9441003 *DOWEL, RR SEAL HSG LOCATOR PIN (7/16")

3701679 *PIN, FLYWHEEL LOCATOR (7/16 X 7/8")

links to a few more part numbers etc.
http://crateenginedepot.com/pdfs/SB_FB385.pdf

viewtopic.php?f=53&t=3951&p=10551&hilit=+flywheel+aluminum#p10551

viewtopic.php?f=53&t=5155

viewtopic.php?f=71&t=447

viewtopic.php?f=53&t=1042&p=1969&hilit=+flywheel+aluminum#p1969
 
Thanks Grumpy for the flywheel info, good stuff.

Got a silly distributor cap question for ya, What the caped hole for on the top of my distributor cap?
 

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its simply a air vent , placed in the top of the distributor cap so engine heat can force moisture collecting inside the distributor cap, out before it can condense and corrode the electrical connections and the rotor, heat tends to make air rise and expand so as the engine heat increases the air trapped in the cap tends to exit thru the vent.
CORROSION DUE TO POOR VENTILATION, from moist air and the IONIZED air inside a distributor, can and does rapidly degrade the contacts, thats why BRASS is usually used , for the contacts the rotor voltage arcs too and theres sometimes a o-ring seal and a vent to allow hot moist air to exit the inside of the distributor cap, vs the much cheaper aluminum contacts in the better brands of distributor caps
 

Concerning the dowel pin.......If it was balanced without the pin and then you
added the pin during final assembly, how much would it effect the balance ???
It's very close to the center of rotation, so that's in it's favor.

 
Not much progress recently but I did get the motor off the stand an on to a dollie ready for flywheel, clutch and bellhousing install
 

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looks like a really clean and well executed build with some time spent attending to the details and cosmetics, congrats
 
grumpyvette said:
looks like a really clean and well executed build with some time spent attending to the details and cosmetics, congrats
Click to expand...

"....some time spent atending to the details....."

Wow ...... did you notice that even the tape over the exhaust ports
was cut straight and not torn off like most people would do. That says something
about whats going on inside the engine. Hell it even matches the color of his engine!!!

Way to go bytor, I'm sure it's going to be a real screamer!!!

 
Thinking through my flywheel, clutch and bellhousing assembly steps. I have a question about the clutch fork and throwout bearing install. I intend on reusing my existing clutch fork so it will come out when I pull the old motor. Can I install the clutch fork and throwout bearing after the bellhousing is installed or does it need to be slipped into the bellhousing before it's bolted in place for the final time?
 
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