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Drive train update time on the mullet mobile, what would you do?

Norm

Norm

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May 21, 2020
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I have a 77 vette, aside from the intake/heads, exhaust, and radiator it's pretty original and in nice shape down to the 8 track. I rebuilt the suspension, brakes , steering etc last winter. The engine is the original shitty L48 2 bolt motor, it was rebuilt in 92, the original th350 transmission was rebuilt in 88 with ~30k on it. The last owner put a leaky holley carb on it and washed out the rings in a couple cylinders and are low on compression, so my plan was to rebuild the drive train this winter. Plus the engine compartment needs paint :homer:. I have some decent newer brodix heads on it, so I'll re-use those. Goals are smooth 400-425 reliable HP. Roller cam, 10:1 compression, basic street machine. I'm not going to ls swap it so :flipoff2:


I'm not interested in cheap internet crate motors or transmissions.

Option 1 - keep the original parts and upgrade. It's not a high $$ year, so it doesn't mean much aside from the full mullet factor. Engine is .030 over but should clean up at .040. It's a 2 bolt, so it needs splayed 4 bolt mains . Machine work will be about $1k total (mains will be ~$500), throw in a scat crank, forged rods and pistons, retro roller cam, 383 stroker maybe. Rebuild the th350 with a 36 element sprag, hd clutches, higher stall torque convertor. Have the diff rebuilt by a vette shop, 373 gears (diff is serial # to the car) . I would loose the vin stamp on the block when it's decked, so keeping the block is probably tarded.



Option 2 - find a 4 bolt 87+ roller core and build that, the rest the same as option 1, It's probably $500 cheaper than option 1 and a much newer block less machine work. I'll also have to run an electric fuel pump because there is no manual fuel pump boss on 87 up. There has to be one sitting in the back of truck in field on the rez I can get cheap.


Option 3 - use a factory new zz4 short block, 4 bolt, forged crank, hypertonic pistons, $2400 delivered. Add my heads and a LT1 hot cam for zz430 clone 430HP/430 TQ. Grab a 2004R core from the trunk of a malibu on the rez and build that for a 4 speed conversion. And have the diff rebuilt by a vette shop, 373 gears


I don't do much long highway driving, maybe a hour or two a couple times a year to car shows or cruises. So a 4 speed auto won't be a big deal other than a lower 1st gear. The 700R4 has the wrong gears in 1-2 so keeping the th350 or a 200r4 swap makes the most sense. Like most projects I'll have way more $$ into the car than it's worth. But it's only money and the lady's at the senior center dig it when I roll by with my Skynard 8 track blasting :laughing:
 
454... because you asked what would you do and that's what I'd do :flipoff2:
 
I'd do an efi conversion on a built roller converted 4 bolt block, I'd also skip the 383 and leave it as a 355 (4.030 bore) and or de-stroke it. 3.73's are pretty low for a 383 that makes torque vs a shorter stroke high revving engine. You could always long rod (6.0") a 355 and have a screamer.

The th350 will be fine with upgrades, you could always do a th350c and gain a lockup converter instead of doing a 200r4.
 
DWT said:
I'd do an efi conversion on a built roller converted 4 bolt block, I'd also skip the 383 and leave it as a 355 (4.030 bore) and or de-stroke it. 3.73's are pretty low for a 383 that makes torque vs a shorter stroke high revving engine. You could always long rod (6.0") a 355 and have a screamer.

The th350 will be fine with upgrades, you could always do a th350c and gain a lockup converter instead of doing a 200r4.
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Eagle makes a forged 3.25" large journal crank, so turn a 350 block into a 327 that will spin 7000 rpm. hmmm
 
Norm said:
Eagle makes a forged 3.25" large journal crank, so turn a 350 block into a 327 that will spin 7000 rpm. hmmm
Click to expand...

7k all day long at that. My uncle's engine builder for his vintage trans am car (67 z/28) asked him if he wanted to spin 10k using a 400 block and a super short crank. If you win too much or really piss someone off they test for displacement, but don't pull heads to check how you got there. :laughing:

He ended up doing a 383 and dropping the rear end down to 3.08s so it still screamed and held together. He was ready to retire so he wasn't competitive enough to get checked, he was just having fun.
 
I'd say big block for giggles. If you want light, go big block cady... just a little heavier than a sbc. Only sucky thing is finding one ;)
 
4 banger IHC gasoline everytime I see a chevy in a ford body I want to do this swap, buddy even has an oily one waiting
 
Just build what you have if you only want 400 horsepower, 2 bolt mains are fine, keep it a 350.

If that`s all I wanted I`d keep the factory crank and rods, put studs in it and have it align honed, then deck and bore the block, torque plate hone etc, recondition the crank and rods, all that good crap, plug a 268 comp cam in it and have the heads gone through and cleaned up by someone who knows what their doing, I don`t care how good the company is most heads come out of the box with something not right, they`ll work but they ain`t right.

My shitbox obs chevy has a similar combo, granted I do have a hydraulic roller block but about the same size cam, 10.7:1 compression, ported factory vortec heads and lower intake and it makes 314hp through 2 inch gutted factory exhaust with a transfer case and 31`s, so i`d guesstimate it makes at least 420 horsepower at the crank, I know this because of what turned out to be a quite profitable day at a buddy`s dyno event.
 
2JZ to rule them all...just need to overnight parts from Japan

or

LS swap, there is a reason its so popular
 
5.7 hemi swap. Hear me out.

You get to piss off everybody. GM guys hate you because you swapped in a non-GM motor. Dodge guys hate you because you wasted their engine on a non-dodge pos. Ford guys hate you because you did what they've always wanted to do but didn't use anything Ford to do it.

win/ win/ win
 
A cam only LQ9 would meet all your goals and probably in surplus. If you wont go the way of the righteous than just build what you have and feel disgusted with the results per dollar. :flipoff2:
 
Lil'John said:
I'd say big block for giggles. If you want light, go big block cady... just a little heavier than a sbc. Only sucky thing is finding one ;)
Click to expand...

I have a late 60s 472 sitting in my shop
 
Brian468 said:
Just build what you have if you only want 400 horsepower, 2 bolt mains are fine, keep it a 350.
Click to expand...

This is exactly right. 2 bolt main and cast crank are just fine. We used to spin them to 11k at the drag strip 40 years ago, never broke one.

I just got done building one. haven't been on the dyno yet. I don't have much money in it. I am not part of the 383 crowd. too old school.

30 over 350 2 bolt main block. originally from a 71 vette not that it matters. My original block was garbage. Ended up with 10.9:1 compression. Figured it is easier to lower than increase if I have pinging issues. Vortec heads. Modified for high lift cam. I am running a 280h comp cam, hyd lifter, flat tappet. (I just like the way they sound, roller is a better choice)
I should dyno 400hp easily. Aluminum mid rise intake. 2100 stall convertor. I built the th350 and added a shift kit. edlebrock spread bore carb. My rpm range should run 1500-5500 ish.

I am actually worried it is going to be too much for the street and not fun to drive. Sometimes they are not fun to cruise in. We will see.

Figured if I really love the car I will eventually do a OD trans swap. But like you said, I have a 78 and not a crap ton of value there.

Have kids that you want to pass it down to someday?
That has been on my mind lately as I get closer to the end of this project. Both my boys are pretty mechanically inclined, But things like carbs and distributors seem to baffle them. So I am kind of wishing or thinking I should have swapped it to something newer and fuel injected, so they would know how to start it and work on it when I am gone.

So if I decide to keep it and it seems wound too tight then I will swap it for newer technology. This build 350 with a dyno ticket will pay for the swap.

Did the suspension, undercarriage, rear end, trailing arms, fuel tank last winter, I am doing all new interior now, engine and trans just went in. I hope to drive it all next summer and then paint it next winter.
 
Wow SBC need splayed 4-bolts to run 400hp? They really are the cheap consumer engine. :flipoff2:

Nah though a '77 vette has been my dream build for a while. Off the shelf parts, full suspension kits for them for $2300 that make all the obvious improvements, stock wasn't bad. You usually start with a 4-bolt but a 2-bolt and modern hardware is good for 500-550hp. A shift kit and with a 3-spd 1970s auto, you are into a seriously quick track or autocross car for not that much money or time. I think a 70s vette set up correctly looks as good and classic as a 250GTO. You can smoke a GTO around the track for $12,000 + price of the vette which isn't stratospheric.
 
Arps said:
2JZ to rule them all...just need to overnight parts from Japan

or

LS swap, there is a reason its so popular
Click to expand...

Anything that can be done to a small Jap motor can be done to a large American motor, and the American motor will make more, better power.

Even from a SBC, stepping back to a 6-popper is at least 2 steps backward. No need to replace 5.7 liters of wholesome American power with 3.0 puny liters of Imperial Japanese cannabilism and torture.
 
Brian468 said:
Just build what you have if you only want 400 horsepower, 2 bolt mains are fine, keep it a 350.

If that`s all I wanted I`d keep the factory crank and rods, put studs in it and have it align honed, then deck and bore the block, torque plate hone etc, recondition the crank and rods, all that good crap, plug a 268 comp cam in it and have the heads gone through and cleaned up by someone who knows what their doing, I don`t care how good the company is most heads come out of the box with something not right, they`ll work but they ain`t right.

My shitbox obs chevy has a similar combo, granted I do have a hydraulic roller block but about the same size cam, 10.7:1 compression, ported factory vortec heads and lower intake and it makes 314hp through 2 inch gutted factory exhaust with a transfer case and 31`s, so i`d guesstimate it makes at least 420 horsepower at the crank, I know this because of what turned out to be a quite profitable day at a buddy`s dyno event.
Click to expand...

Any SBC or SBF should be a roller cam regardless of block vintage after.... 1962 right?.... and make 400+ hp.

There are many videos and stories of people taking assembled AFRs to the head shop to get valves centered, seated, re-do the valve job, replace seats, etc. I figure I will be buying naked heads unless the combos come out cheaper and you still pull them apart and send it all to the head shop. There's too much lying on the floor with assembled heads. Assembled heads are for racing and building swappers. Say 80% of the aftermarket won't care about longevity engines, but I want to build a 400whp short-deck Windsor that goes 200,000 miles and still makes great power at 200,000 miles. This should be easy and one of the steps I've determined via diligent Web Wrenching is that the full head treatment is justified in all cases. Under $500 to look at and fix the 2-5 problems every AFR or Twisted Wedge or Dart will have. At least one valve out of center out of 16. Still within tolerance of the valve manufacturer and head manufacturer, but out of tolerance for whoever is writing books for valve trains. It's a weird subject, at first I thought it was head shops trying to stay in business but it makes sense and enough evidence.
 
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