My wife is getting another heart.

[Recon]

Well my wife is my land yacht, sue me. She’s getting another engine. It’s a real L78 396 big block. Some factory upgrades over the regular 396 include: 780cfm Holley carb, aluminum intake manifold, square intake port heads, 2.19in intake valves, 1.72in exhaust valves, 11:1 compression, 4 bolt main block, forged steel crank, solid lifter cam. It has very few upgrades/changes, as the car itself competes in stock class at shows. We did a hotter hydraulic lifter cam for maintenance, roller rockers, headers, and lowered the compression to 10.58:1 for fuel options. It was already bored before my purchase.
My car is a real 65 Impala SS, factory 4 speed, with its original powertrain in it. When we purchased the car, it wasn’t in the greatest of shape. My father always wanted a big block in it, but at the time the 300HP 327 was enough. I decided that if anything ever happened to the original engine; there were 3 engines I’d like to replace it. This 396 being one of them. The reason being in 1965 was the only year you could get a 396 in a Corvette. They came in two flavors 375hp and 425hp. Ironically there wasn’t a nickels worth of difference in the two engines. They revved it a little more and it produced the 425hp. Well the 425hp 396 was available for a 65 Impala.
Due to the car being originally a small block car; we’re having to upgrade components to handle the big block. First is a big block transmission. The car originally has a Muncie M20, it’s getting a Muncie M21. Second, it has drums on all four wheels, and disc brakes will be added to the front. Third, are the front end suspension components. They need to be upgraded to handle the heavier big block. The car won’t be drag raced so everything will be based on stock equipment standards.
A lot of pictures were taken at the machine shop. As I receive them I’ll post them up.
I’ll update this thread as the endeavor continues.


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[Recon]

Cam specs.


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[Recon]

Hurst shifter and 3.73 gear upgrades.


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[gimmie11s]

Looks like fun!!

 

[Papaw]

If the gross duration is .290 then the exhaust duration at .050 would be somewhere in the .230's like the intake, still, a healthy street cam and with 110 degree lobe separation it will have a nice rumble. Nice build!

 

[Junior00]

Thought the M20 had a lower 1st, always preferred them over a 21 in a big block because it kept the torque band longer with the wider spread.

That said, I know they can regear a 22 with the wider spread which is awesome.

 

[CobraBob]

This is going to be a nice build thread to follow. Can you post some current pics of the car?

 

[Fastback]

Right on! Put the rectangle ports to work! My old man has a pair on his big block Chev. Running a Howard Rattler' Cam. All this in his grandma's 72 Nova Haha!

 

[TK1299]

If the gross duration is .290 then the exhaust duration at .050 would be somewhere in the .230's like the intake, still, a healthy street cam and with 110 degree lobe separation it will have a nice rumble. Nice build!

 

[Recon]

Thought the M20 had a lower 1st, always preferred them over a 21 in a big block because it kept the torque band longer with the wider spread.

That said, I know they can regear a 22 with the wider spread which is awesome.

The intention is to preserve the original transmission. A close ratio M21 is what they recommended and that’s the replacement transmission. The 12 bolt is staying as it’s not at risk of being damaged. It won’t be a drag car ever. If I decided to get a little frisky with it I didn’t want to damage my original transmission.


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[Recon]

This is going to be a nice build thread to follow. Can you post some current pics of the car?

As she sits in the building. Forgive the dirty tires. I haven’t cleaned her in some time.


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[Recon]

The 780cfm Holley. Recently restored by Holley. Thankfully they’re close by.


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[Recon]

As she sits now.


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[Recon]

If the gross duration is .290 then the exhaust duration at .050 would be somewhere in the .230's like the intake, still, a healthy street cam and with 110 degree lobe separation it will have a nice rumble. Nice build!

Well to be honest we had another cam ordered and it was delayed for over 3 months. The decision was made to get something kind of close so we could get the engine done. My birthday is in January and I wanted to drive it on my birthday given if the roads were in good condition. They weren’t and the engine wasn’t ready. Next goal was my father’s birthday in April. That didn’t happen either; so, we just wanted to get the engine in the car before the show season was over. Given that’s a while from now, but we still have to get everything prepared for the car to handle the engine.


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[tones_RS3]

Awesome stuff.
Keep us posted.

 

[Recon]

Guess this deserves an update. After an ridiculous amount of trial and errors; it seems that the car is pretty close to being legitimately operational. We also had A LOT of incorrect parts. A few things have changed since the last update.
The car now has a M22 Rock Crusher out of a 69 Chevelle. It now has the very best of what Chevy offered in 65.
We weren’t really getting anywhere with getting parts for an Impala; so, we started getting parts for a 65 Corvette. Which seems to be working pretty well for the most part.
Another change is the valve covers. The spacers were a bad idea. I looked for a while and finally found some I liked. They’re tall deck big block replicas of the C1 Vette small block valve covers.
We found an original big block radiator that we had repaired. Well it’s leaking so I have a temporary solution. I have an aluminum radiator that will be used until the brass one is available from classics.
We waited a long time for the alternator due to it not matching the mounting brackets. Well it turns out the lower mounting bracket was wrong. But that’s taken care of now.
Another temporary solution is the Edelbrock fuel pump, first one was wrong. Pretty much I’m to the point of getting the damn car drivable. All the little details we’ll get done later.
The carb was sent off to Holley for refinish of the metal and refresh. That happened very early in the build. Well they put the wrong jets in the carb.
As she sits currently. There’s a possibility of the distributor being bad, the second one. We have a scope here to verify that. We drained the old fuel out of the tank. It currently has a mix of 93 ethanol free and 110 leaded race fuel. 5 gallons of each. There’s a temporary exhaust setup on the car until it’s running good. Exhaust manifolds with 2.5in pipe going to Super 44s dumped.
That’s all that comes to mind right now. I’ll post more as it comes back to me.
Here’s the engine as it sits:

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[Recon]

Update.

Distributor is bad. Thanks to the scope for clarifying. We spoke with our machine shop in Clarksville to get some clarity on a few things. The machine shop recommended a different distributor, and it will be here on Friday.
Headers are too big for the set up. I called Hooker and that’s all they offer for the big block. They said a set from a first Gen Camaro might work, but it’s just marginally smaller. The topic of it even fitting my car is another toss up. So, I’m going to look at other brands that offer what we need, but there’s still a possibility of the Hookers going on engine. I really wanted them on the car.
I had a suspicion the cam was incorrect. We had someone assisting us in getting the cam. This was during a cam shortage, and options were extremely limited. My wishful thinking deadline, at the time, was getting pretty close to arriving. The cam that was ordered still wasn’t in stock. So, another cam that was in stock was ordered. I had the specs of the cam already. I wanted to do some comparisons to another cam I heard. I find mine online, and it gave some engine stats. My concern was the CR wasn’t close to mine, as in lower. After speaking with our machine shop; it’s all good.
The other issue was I have doubts that the car would sound the way I wanted it to sound. Which is a reoccurring theme. I grew up in an exhaust shop, and I’m particular when it comes to exhaust notes. But as we’re this close to getting the car running good; I’ll wait until I hear it when all the intended exhaust parts are on the engine.
That’s all for now.


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[Recon]

The radiator is in, and we had to get another lower hose. The previous one had to be shorten to fit the much larger original brass radiator.

I’m not sure if you can tell the positive batter cable clamp is broke. So, new cables will be ordered tomorrow. There’s a few things that also need some attention. The fuel line, from pump to fuel filter, is touching the lower radiator hose. We have a section of the old hose In between them. That will be resolved soon.
As of today, Independence Day, marks the first day I drove the car. Now given it was only about 100 feet. Reason being is the car was fuming up the building pretty bad and with the race fuel mixture it’s wasn’t great for the eyes and nose. I had a few impressions from it. The shifter is extremely notchy which I like. Although there will need to be some adjustments made as she wasn’t real happy going into reverse. Quick note is the shifter assembly was labeled as for a 65 Impala. I found out later that, that was incorrect, imagine that. It was for an earlier Impala. One thing that we had to do was trim the reverse level at the shifter as it was making contact with the transmission crossmember.
The clutch seems to not changed its characteristic of being very stiff. Not a negative trait as I’m used to it; having this car for so long. Throttle response is great. Today was the first day the throttle linkage was hooked up. It’s also a nice touch that after 14 years of ownership the car will finally have a functional choke set up. When the car was restored several years ago not choke parts were available for my small block with the original carb.
We had a coolant leak outside and it was the radiator clamp at the thermostat housing. That’s taken care of and thankfully not much coolant was lost.
After the final session of fine tuning the carb and adjusting the timing; I can say she runs great. And man my constant doubt, of the cam not meeting my high expectations, is out the window. The car is talking a lot of shit at an idle, and I love it.


Sent from somewhere in the twilight zone…