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Discussion Starter #1
Came across an amazingly clean barn find elky and the price is reasonable- just hashing out the details. I have a 489 sitting in pieces that was going in my 1984 Cutlass, but I'm going to scrap that car and use parts from it for the elky. My question is how strong is the body of an ElCamino compared to my Cutlass? I have a bolt in 9inch for the back so the rear end is covered. I also have a well built turbo 400 transmission. What I don't know is how much the body can take. The engine will produce well north of 500 ftlbs of torque and hp will be around the 500 mark. It is a street oriented engine, not a race engine and the car will be geared as such. Right around the 3.23 to 3.31 ratio. I have 3.42s in my Cutlass with a 408 BBC and I'm not comfortable spinning the 489 that high at cruise. It will have plenty of grunt for a numerically lower gear. However, 1st and 2nd gear will still have plenty of frame twisting torque which concerns me. Am I worrying too much about this on a street car? Anything I should look out for?
 

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El Camino has a stronger frame, it is boxed full length under the rocker panels....much stronger than the Cutlass frame. Other than the boxed center section of the frame, and the added 9 inches of length for the longer wheelbase, the frame is otherwise exactly the same as the Cutlass frame, suspension on each end is all the same.

If you want some more strength replace all the body bushings with either solid aluminum or poly, the body and frame will act as trusses and add support to each other, making the platform more stable in it's entirety.
You may also be able to find something similar to this kit for the early A-body if you search beyond Summit or Jegs.
Summit Racing SUM-770800 Summit Racing® Frame Brace Kits | Summit Racing

Body is virtually the same...in fact, under the front section of the bed floor the original sedan/wagon back seat floor pan and footwells area is still there, including even the seat belt mount locations!!!,.... just covered over by the bed floor and turned into the spare tire area.

The 489 will handle the 3.42 cruise rpms just fine, no need to be worried about it....unless a complete disaster of a build it would handle sustained 4000 rpm down the freeway without a blink.... if your ears could withstand the reverberation noise.

3.42 switched to 3.31 or 3.23 is a waste of time, you will barely notice the difference at cruise....the 3.31 would drop 75 rpm, the 3.23 would drop 140 rpm.

Just a note, common 9" Ford ratio's are 3.50, 3.25, and 3.00....they don't have 3.42, 3.31, or 3.23 .
there is a 3.40 available, but it tends to be quite a bit more expensive.
 

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I know you have the 400 transmission, but seeing you want a cruiser more than a racer, have you thought about a 700r4, the overdrive would really drop the RPMS for you going down the road
 

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Discussion Starter #4
El Camino has a stronger frame, it is boxed full length under the rocker panels....much stronger than the Cutlass frame. Other than the boxed center section of the frame, and the added 9 inches of length for the longer wheelbase, the frame is otherwise exactly the same as the Cutlass frame, suspension on each end is all the same.

If you want some more strength replace all the body bushings with either solid aluminum or poly, the body and frame will act as trusses and add support to each other, making the platform more stable in it's entirety.
You may also be able to find something similar to this kit for the early A-body if you search beyond Summit or Jegs.
Summit Racing SUM-770800 Summit Racing® Frame Brace Kits | Summit Racing

Body is virtually the same...in fact, under the front section of the bed floor the original sedan/wagon back seat floor pan and footwells area is still there, including even the seat belt mount locations!!!,.... just covered over by the bed floor and turned into the spare tire area.

The 489 will handle the 3.42 cruise rpms just fine, no need to be worried about it....unless a complete disaster of a build it would handle sustained 4000 rpm down the freeway without a blink.... if your ears could withstand the reverberation noise.

3.42 switched to 3.31 or 3.23 is a waste of time, you will barely notice the difference at cruise....the 3.31 would drop 75 rpm, the 3.23 would drop 140 rpm.

Just a note, common 9" Ford ratio's are 3.50, 3.25, and 3.00....they don't have 3.42, 3.31, or 3.23 .
there is a 3.40 available, but it tends to be quite a bit more expensive.
Eric, your knowledge is something I value and I always hope to hear from you when I post. I like the poly bushing idea; will look into that.
Here's my take on the gearing: I know the engine can handle the rpms, I just think with that much power it doesn't need to spin too many rpms. I also keep forgetting I have a crappy B&M 2400 stall so with a 26 inch tall tire I spin about 3 grand at 60 mph. You've reminded me before that a good convertor will not slip so bad. I'm looking at a 2800 stall 10 inch that is in the 700 dollar range and will be right for my combo with the 3.42 gears.
Thanks for the info on the gears and changes.
I'm gonna have to do more research on El caminos, I don't know much about them. You clued me in on a few things I never knew about them.
Any more info I might need?
 

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Discussion Starter #5
I know you have the 400 transmission, but seeing you want a cruiser more than a racer, have you thought about a 700r4, the overdrive would really drop the RPMS for you going down the road
Actually I have kicked around the idea of an overdrive transmission. Problem is building one to survive that kind of power. I absolutely hate the 700r4 because I feel the gearing in them is stupid; and they're finnicky. The 4L80E requires tunnel work, and the 2004R costs a mint to take that kind of power. The 400 I have was cheap to beef up and will take a beating daily without complaint.
However, if you have an idea about something I didn't think of, I'm all ears. I'm always willing to learn.
 

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If you can find a '68-72 Chevelle or '70-72 Monte Carlo transmission crossmember, it is easily modified to fit the later metric A/G-body and gives you a clearance hump on each side for dual exhaust(stock '80-Elky crossmember has just one pipe hump for single exhaust).
Each end get trimmed an inch or so shorter, and some new bolt holes drilled but fits great.
There are aftermarket dual hump crossmembers too, if you don't have any of the '68-72 stuff near you.

As far as differences in the '78-87 El Camino, that boxed frame is about it....everything else is the same on similar year metric A/G-body.
 

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Discussion Starter #7
If you can find a '68-72 Chevelle or '70-72 Monte Carlo transmission crossmember, it is easily modified to fit the later metric A/G-body and gives you a clearance hump on each side for dual exhaust(stock '80-Elky crossmember has just one pipe hump for single exhaust).
Each end get trimmed an inch or so shorter, and some new bolt holes drilled but fits great.
There are aftermarket dual hump crossmembers too, if you don't have any of the '68-72 stuff near you.

As far as differences in the '78-87 El Camino, that boxed frame is about it....everything else is the same on similar year metric A/G-body.
I actually have a dual hump crossmember in my Cutlass for the 400 tranni. It'll fit the elky won't it?
Also, is that an A or G body in 1980?
Is the rear end the same width and style as my Cutlass?
Oh, and get this: in my travels today I came across a 1980 El Camino that's an original stick shift. Body is shot but it's all there. I knew the guy that owned it, I bet the v-6 is no longer under the hood lol.
If I do put the 489 in it will my big block headers from the Cutlass work okay fitment wise?
As I said, I know very little about these cars.....
 

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I agree gearing sucks on 700r4, as for cutting the floor pan for a 4l80. I have seen tunnel kits that make it a little easier

But I understand having a budget, use 400 and keep your eyes open for a good 200 or 4L80
 

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I actually have a dual hump crossmember in my Cutlass for the 400 tranni. It'll fit the elky won't it?
Also, is that an A or G body in 1980?
Is the rear end the same width and style as my Cutlass?
Oh, and get this: in my travels today I came across a 1980 El Camino that's an original stick shift. Body is shot but it's all there. I knew the guy that owned it, I bet the v-6 is no longer under the hood lol.
If I do put the 489 in it will my big block headers from the Cutlass work okay fitment wise?
As I said, I know very little about these cars.....
Other than the added 9" of frame and wheelbase length, and the fully boxed rocker section of the frame, everything else is the same as your Cutlass. You may run into minor differences between 1978-80 and 1981-87 such as front wheel bearing size being different the first year of the metric platform or other such minor differences.
The GM midsize platform was still called A-body after the major redesign and size reduction of the metric chassis for 1978, but was still called an A-body from '78-80 and then designation was switched to G-body....but '78-87 GM midsize metric RWD platform is what it is underneath.

Everything for the chassis/drivetrain you have for the '84 Cutlass is the same application, bolts right up. You'll need a longer driveshaft though than the Cutlass has, and I would not trust a stock GM 1980 Elky driveshaft to put up with much increase in power, most of those metric chassis stock shafts are really lightweight, thin wall and undersize on diameter for less rotating weight and increased fuel mileage. 350 hp would be stressing it pretty high.

The stick shift pedals and linkage was a good rare find at one time(y), I don't know if you can currently get them as resto parts or not.
 

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Discussion Starter #10
Other than the added 9" of frame and wheelbase length, and the fully boxed rocker section of the frame, everything else is the same as your Cutlass. You may run into minor differences between 1978-80 and 1981-87 such as front wheel bearing size being different the first year of the metric platform or other such minor differences.
The GM midsize platform was still called A-body after the major redesign and size reduction of the metric chassis for 1978, but was still called an A-body from '78-80 and then designation was switched to G-body....but '78-87 GM midsize metric RWD platform is what it is underneath.

Everything for the chassis/drivetrain you have for the '84 Cutlass is the same application, bolts right up. You'll need a longer driveshaft though than the Cutlass has, and I would not trust a stock GM 1980 Elky driveshaft to put up with much increase in power, most of those metric chassis stock shafts are really lightweight, thin wall and undersize on diameter for less rotating weight and increased fuel mileage. 350 hp would be stressing it pretty high.

The stick shift pedals and linkage was a good rare find at one time(y), I don't know if you can currently get them as resto parts or not.
Okay eric, new question. I just learned today there was a turbo 350c transmission that was released in 1980. The '80 Elcamino I'm looking at has a 305 v-8 in it. Any idea what transmission would have come in it? The car is not accessible to me right now.
 

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Most likely it is the 350C, the lock-up converter TH-350...but it could just be a regular TH-350 still.

The light duty TH-200 didn't get put behind V8's that I know of, even the litte 267.....just the various V-6's got those if my memory is correct.

No TH-400's were used at all.
 

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Most likely it is the 350C, the lock-up converter TH-350...but it could just be a regular TH-350 still.

The light duty TH-200 didn't get put behind V8's that I know of, even the litte 267.....just the various V-6's got those if my memory is correct.

No TH-400's were used at all.
If it is the 350c, can it be built to take a 489s power? I like the idea of a lock up convertor at cruise in a three speed. It's my understanding the 350c is weaker from the factory than the older turbo 350.
I assume stall convertors are made for this tranni?
 

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I can't really tell you anything on the 350C. I know the input is weaker because of the lock-up shaft, and that there is very little performance usage of this trans, and that both the case and the valvebody are diffeent from the regular 350 due to the additional oil passages for the lock-up . Almost no performance valvebody kits, zero manual valvebody or transbrake available. No clue if anybody make a stall converter for it.

We always just tossed 'em on the scrap pile.
 

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Discussion Starter #14
I can't really tell you anything on the 350C. I know the input is weaker because of the lock-up shaft, and that there is very little performance usage of this trans, and that both the case and the valvebody are diffeent from the regular 350 due to the additional oil passages for the lock-up . Almost no performance valvebody kits, zero manual valvebody or transbrake available. No clue if anybody make a stall converter for it.

We always just tossed 'em on the scrap pile.
Okay, thank you. This is good to know. I will just plan on using my 400 as it is already built to handle the power. The one thing I don't like though is I put a B&M transpak? kit in it many years ago and the 1-2 shift is just brutal. I assume this can be reversed but what about the check balls that were tossed? Is there a kit that comes with them?
I'm looking for firm positive shifts but not the neck snapping shift I have now. (getting older I guess).
I want to do this elky right and build a nice pleasurable to drive vehicle. The 489 will be more street oriented because this will be a driver, not so much a racer.
At 47 I've reached a point in my life where I still love stupid power but don't care for speed anymore. I like comfort and drivability. I want to get in it and drive two hundred miles without fighting it or going deaf because of loud exhaust.
So, that's the way I will build this car.
 

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I think the only way to reverse the Trans-Pak deal is a new kit....I believe it is hole size in the seperator plate that determines how hard it hits(they have you drill it for shift firmness level in the instructions, remember?), along with removing the accumulator cushion spring on the 1-2 shift accumulator and turning the dup upside down when reinstalling it to reduce the volume.
You could try putting the cushion spring back in the accumulator, or maybe just putting the accumulator cup back in the correct orientation so it's volume acts as a cushion.

It's not a check ball issue as far as I know. Been a long time since I used a B&M kit though....I usually used Fairbanks for those 3-in-One level kits.
 

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Discussion Starter #16
I can't really tell you anything on the 350C. I know the input is weaker because of the lock-up shaft, and that there is very little performance usage of this trans, and that both the case and the valvebody are diffeent from the regular 350 due to the additional oil passages for the lock-up . Almost no performance valvebody kits, zero manual valvebody or transbrake available. No clue if anybody make a stall converter for it.

We always just tossed 'em on the scrap pile.
I did some digging and found several shift kits and many different stall convertors available for the 350c. And it turns out there are some performance rebuild kits for them too.
 

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I did some digging and found several shift kits and many different stall convertors available for the 350c. And it turns out there are some performance rebuild kits for them too.
Good info....I hadn't messed with a 350C since about 1995-ish.
Probably the trend for lock-up overdrives helped the market for the 350C by way ot trickle down tech.
LOL I knew a lot of guys just scrapping them out in the 1990's...piles of them.
Back then nobody built a converter clutch that could handle any decent power, so the 350C was cast aside.
 
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