81 engine rebuild questions
Thread Starter
Instructor
Joined: May 2013
Posts: 167
Likes: 3
I wanted to thank everyone for their suggestions and help on this thread. I’ve decided to go a different direction.
Going to take this motor out and put another in. I have a friend that’s been a mechanic for probably 30 years, and now is a mechanic for a classic car restoring business, and we are going to do one of 2 things.
He has a 350 sitting there with double hump heads that came out of an older corvette or Camaro. So either that will get rebuilt and go in there , or do an LS swap. He’s done quite a few of them and is currently doing one on a 63 split window.
Not sure which way I’ll go, but again thanks for all the ideas and help on here.
Going to take this motor out and put another in. I have a friend that’s been a mechanic for probably 30 years, and now is a mechanic for a classic car restoring business, and we are going to do one of 2 things.
He has a 350 sitting there with double hump heads that came out of an older corvette or Camaro. So either that will get rebuilt and go in there , or do an LS swap. He’s done quite a few of them and is currently doing one on a 63 split window.
Not sure which way I’ll go, but again thanks for all the ideas and help on here.
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
If you go with the older 350, ditch the double humps and get a pair of Vortec heads. Stroke it for even more fun.
You can also find a later model 350 vortec long block and get hydraulic roller valvetrain for an added bonus.
You can also find a later model 350 vortec long block and get hydraulic roller valvetrain for an added bonus.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
I would not mess with either the Vortec or the Double hump heads.........the Vortec's have to be modified for over .450 lift if stock...they can be bought with the mod but it increases the price to around what a real aftermarket head is......the Vortec also requires one head to be drilled for cooling bypass and a specific intake that will never fit anything else. Don't get me wrong....the heads work....but they are done at around 400 horsepower....a lot of work for heads that are at the end of their potential...
Just put a top end and cam kit on what you have......I have done that about 50 times over the years for people.
The Trick Flow 175cc head they just released is proving to be the cats *** for these older 350's.......I like Dart myself....but an aftermarket head is the way to go.....costs a little more but parts remain interchangeable and you stay away from self aligning rockers and all that crap......
There is nothing in that "double hump" engine that is any better or benefit than the engine you currently have........if the bottom end is solid......upgrade it!!!! All those standard 23 degree parts will work on the engine you want to build in the future......
Jebby
Just put a top end and cam kit on what you have......I have done that about 50 times over the years for people.
The Trick Flow 175cc head they just released is proving to be the cats *** for these older 350's.......I like Dart myself....but an aftermarket head is the way to go.....costs a little more but parts remain interchangeable and you stay away from self aligning rockers and all that crap......
There is nothing in that "double hump" engine that is any better or benefit than the engine you currently have........if the bottom end is solid......upgrade it!!!! All those standard 23 degree parts will work on the engine you want to build in the future......
Jebby
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
quite recent ... Real Budget Vortec Engine Build ... seems build began Fall 2018 ... dynoed last month
creative valve angles etc
long, detailed thread, hard results begin about page 5: Budget 355 Vortec Build (project Dale) ... dynoed +480fwhp, 465tq
https://speedtalk.com/forum/viewtopi...55269&start=60
creative valve angles etc
long, detailed thread, hard results begin about page 5: Budget 355 Vortec Build (project Dale) ... dynoed +480fwhp, 465tq
https://speedtalk.com/forum/viewtopi...55269&start=60
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
I've bought several 5.7L vortec 4-bolt longblocks for $250. The guides can be cut down with a drill, it's not a big deal. No need for more than about .525 lift anyway. Clean up the short turns and bowls a bit - same as you'd need to do to ANY aftermarket head out of the box. You can stroke it for a decent price and even reuse the stock powder metal rods. You'll only be out the cost of the crank and pistons will be a wash since you'll need new ones anyway. These powder metal rods are cut-cap, so they can be resized, not like the fractured caps on some of the LS engines. You'll save a lot on lifters (LS7 sets are available on ebay for $150) as compared to retrofits in an older block. There's no reason to go with a flat tappet cam in today's world, more lift and duration for the same advertised numbers and no worries about flat cam lobes.
My son built a stroker for his high school project with an LT4 cam. Ran fine in his computer controlled '98 Tahoe and made plenty of power to move that barge really well. You can build a mill for a reasonable price with all GM parts that will be a helluva lot of fun on the street.
My son built a stroker for his high school project with an LT4 cam. Ran fine in his computer controlled '98 Tahoe and made plenty of power to move that barge really well. You can build a mill for a reasonable price with all GM parts that will be a helluva lot of fun on the street.
Last edited by L88Plus; Apr 20, 2019 at 09:00 PM.
