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Project: 1965 Corvair Kelmark V8 - What motor / recipe?

15K views 28 replies 7 participants last post by  mikebuongiorno 
#1 ·
Hello World,

First post ever. Revisiting a project started in the 90s by another, bought by me in 2004, worked on feverishly, then left to sit while raising kids, moving/saving bigger house, etc.

I've got a little bit of a war chest rebuilt and need to finish this project for my soul.

Its a 1965 Corvair Corsa setup for a mid engine Kelmark V8 conversion. Radiator plumbed in the front with copper tubing, disk brakes, 15" wheels, etc. Missing one critical component. The Engine.

Reaching out to the team (long time reader, first time poster) to help with engine selection / build recipe.

Want to build a fun to drive, decent mileage, decent power v8 car that doesnt brake my driveline. I understand the diff and input shaft are weak links. I'm running the hardened, 1" longer aftermarket shaft, and a 66 saginaw. Spider gears in the diff. Even still, what I've read is to keep hp and torque under 300 to be safe. People get away with more I've read but the standard SBC torque is what kills this setup as far as I can tell. The finished car will weigh between 2500-2700lbs.

What I'd like to build is something that will reliably rev to 6-7k, making good power between 2-7,000 rpm happily sacrificing low end torque to keep my driveline alive.

To do this I'm weighing these options (budget for finished motor is <$5k).

1. Get the 350/290 from jegs, run it for a while, see how it does, then move to aftermarket heads and longer duration cam to meet my goals.

2. Get the 350/330 and do as above, hoping with the torque that motor puts out, I'm not replacing my shaft and diff straight away.

3. Get the vortec truck motor (L31), deal with the electric fuel pump issue, but benefit from the better heads and roller cam setup, change out the cam down the road and see how much I can squeeze before I find a weak link.

[www.jegs.com]

All that being said, what do you guys think? Am I on the right track?

what way would you go? I'm not that savvy when it comes to all the SBC variables, but the obvious inputs for you gurus are relatively light car, low end torque is DANGEROUS, want to rev relatively high to drive this car as a mid engine roadster with great handling on windy roads.

Got some money burning a hole in my pocket and dying to get to driver status. Or should I just say screw it, save more money and lose (way) more time and just go LS1 and some other driveline all together. Would love that obviously, but a driver within site if I go Gen 1 SBC, way out in dreamland if I go LS1.


Thanks in advance for the wisdom.

-Mike
 
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#3 ·
One of my childhood dream builds was in fact a mid ship Crown Corvair.Back then the engine of choice was the 327's,but there where 350's swapped in them.

I know you said to exclude the LSx option.But to bring his to current day engines that fit your requirements the 5.3's is almost too prefect to be true.They are cheap to get and you get a engine that responds to a turbo very well and again right within the power curve you want with the power train you have to work with.Winding roads driving with a turbo behind you,yeah life shouldn't be that good.
 
#4 ·
Already have engine mounts welded to subframe for gen 1 v8, and have the kelmark adapter for the gen 1 to corvair diff.

Going with a modern block (LSX or otherwise) would require new adapter and new motor mount locations correct? I feel like the car is so close to drivable should press forward with gen 1, otherwise, its a longer term project and if were to change mount location and adapter, would be inclined to change diff and tranny as well.

Could I find the right bump stick for the 350/290 crate that put the torque down under 300, and still give me ~300+ horseys at 4-6k? Any recommendations?

Thinking 600-650 cfm carb, ram horn manifolds (the engine is in the middle of the car).

-Mike
 
#11 · (Edited)
Like 1Gary, I had the Crown catalog and was chompin' at the bit to build one of these. You know how providing for the family has a way of cooling a hot desire though and I never got around to it.

I would build a low compression 350, around 8.5:1, but with a decent set of heads.
I'd want a cam with a wide LSA, maybe something like this Crane cam.....

Great for 305 HO and performance 350 trucks, good mid
and top end torque and HP, axle ratios of 3.73 or numerically higher required, auto or 5-speed manual.
Grind number 2040
Power range 1600-5400 rpm's
Part number 114132
Lifters part number 99277-16
Springs part number 99848-16
Intake/Exhaust duration @ 0.050", 210/216
Advertised duration 270/276
Lobe separation angle 114
Timing events (4), 34, 47, (11)
Valve lift 0.440"/0.454
Intake valve closes at 34 degrees ABDC @0.050" tappet lift
Dynamic compression ratio is 7.5:1 on the KB calc. Should make an easy runner that will operate on any kind of cheap fuel and make good power upstairs to 5400. I'd use a Weiand Street Warrior intake manifold. It matches the operating rpm's of the camshaft.
Holley Performance Products Street Warrior™ Intake Manifold*8120
 
#12 ·
Doesn't include the size of LSx's but will give you first gen's to compare against.

Popular American V8 Engine Dimensions

The only other thing to be considered is the LSx's are a one pc rear main and would require a flywheel for the same.Really not a big problem because of LSx's that come with T56's.Good thing is a hydro throw-out bearing which would make hooking it up to a master pretty easy.

The 5.3's can be had from pick and pulls for a range of $300 to $500.Then fashion a junk yard turbo off a import car.I don't think the external size of a LSx is any bigger than the first gen's.:thumbup:
 
#19 ·
kelmark

The kelmark config (mine) goes block, diff, tranny. Plenty of legroom over the crown (about a foot more I think) A quill shaft/input shaft is weak link though, and the ring gear spins in reverse.

http://t0.gstatic.com/images?q=tbn:...qhVAGeeLQ0-HTWphExU8W5v2pMAn8JxiM9EFzh_hEDgXw

http://t0.gstatic.com/images?q=tbn:ANd9GcQ7SR-0f965D5P4X0Fe63RLjzXRs2-ecNZ1Lr0O_qjkV6nrn9ewVIIWSAMh

What are some of the hot rod tricks I can employ for dealing with the torque shock on that shaft ? Does a 11-12" clutch with heavy duty springs help? Does a heavy flywheel / balancer combo help?

Found a guy with a zz4 crate, practically new, roller cam, aluminium heads, for $800. Thinking cam that thing and exercise restraint !

So many options, so to summarize whats on the table:

-zz4 crate for $800 with 500 autocross racing miles on it (feels like a good deal)
-new 350/290 from jegs $1900 (i like this too, mostly for the price)
-Craigslist 283 or 327 (feels like the right CID to save the driveline)
-Gen III smaller displacement crate (have no experience with this)
-aluminium 215 rover (would be an awesome option, keeping the car light has tons of benefit)

My ultimate goal is light mid engine sports car for windy roads that will wind up to 6000-6500, 300HP/300TQ < $5k complete is the goal. With the budget I think the 215 and the gen 3 with computer will be tough, a new or pr

The
 
#26 · (Edited)
Right, but don't sell anything off the donor until your project is finished and running down the road. Ask me how I know.
I'd start with the local little newspapers from the grocery store. If you know all the cars/trucks that had that motor in them ahead of time, you could scan those papers first. I used to drive around and look behind fences/barns/abandoned buildings and sometimes I'd find one sitting at the edge of the road or the curb in residential areas. I wouldn't go to a boneyard except if there is no other way. Check the local auctions such as police auctions. Look on craigslist. I used to check the section "Projects" in Ebay Motors.
 
#29 ·
LM4 / LM7 Gen 3 snag

Hit a (major?) bump.

The gen 3 requires as far as I am reading a 14 1/8" 168 tooth flywheel.

My kelmark special adapter for SBC to corvair diff is 14." Plus the gen 3 pushes the flywheel into the bellhousing / adapater 0.4" deeper. Looks like I need to scrap the gen 3 plan, or mill out my adapter (if even possible) or cast / fab a new adapater (not gonna happen).

Anyone know of a work around I might not yet have read about?

most of my info is from this very nice car craft article on using gen 3 and classic trans (my config is the corvair diff and saginaw 4 speed).

Engine and Transmission Swap Gen III - Car Craft Magazine


-mike
 
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