20mercury

Got a 427 L68 in a 1969 Corvette I am getting ready to rebuild. Found out the L68 is the same as the L36 (390hp) but with the Tri Power Holley carbs.

Happy to build back all OEM stock, 10.25/1 compression as it will be a Sunday afternoon cruiser with pump gas.

What is and who has the best 427 stock rebuild kit including pistons?

Thanks!

blue427

P.A.W. was good,Summit and Jegs are good,but you might have to ask tech for 427 pistons as most pistons are for 454's.P.A.W. even had the right no's for the 390 and 400hp cams.

derekderek

Tear your engine down and see what you need. If bores are good, rings and bearings may be all you need. If you don't need pistons, you don't need rebalancing.

20mercury

This is one of these purchases that is labeled "needs complete assembly, some but not all parts are included"

Got the 427 block (L68, so 10.25/1 compression) which has been bored .020 over and magnafluxed ok, plus crank plus reconditioned rods. So definitely have to buy pistons/bearings/gaskets/rings. And glad you brought up the rebalance as I think the 427 was internally balanced and the 454 was not, maybe?

So, need the rebuild kit with pistons, ect. Ebay and Summit (can not figure out the P.A.W. link for some reason) has them but I was wondering what vendor has a good kit. Happy to go back stock. Some of the performance pistons look to be pricey to me and not really needed for me I think anyway. Any 427 rebuild suggestions are welcome.

TimAT

$27 BBC is internally balanced. Check with places like CNC Motorsports, Ohio Crankshaft, Shafiroff Motorsports, Steve Schmidt Engines for rings and bearings too. You'll need a good machine shop to press the piston pins out and back in. I'd also look at having the rods reconditioned and installing ARP bolts in both the rods and mains. If you change to ARP main bolts or studs, I'd think that having the block line honed might be a good idea too.
And with that, maybe your machine shop could get you a better deal on the rings, bearings and gaskets,

ddawson

I would talk to Wolfdog and have him get you the parts you need.

http://www.lewisracingengines.com/

That way everything matches. If it was me I'd go to 30 over with TQ plates.

calwldlife

i am not aware of any kits like you asked about.
i guess gm might?

gasket sets, yes
rotating assmy, yes

regardless, if i read the info right? block is at .020 over?
this size could limit choices.

me, i think i would recondition rods and have them converted to full floating.
have a machine shop with pistons in hand match to cylinders.
have hone done to ring choice
balance
crank Chanfered drilled polished.
lifter bores checked
use clevite bearings
melling pump

20mercury

Thanks for all of the suggestions and feedback.

Here is one kit from ebay:

https://www.ebay.com/itm/Chevrolet-V...53.m1438.l2649

and another:

https://www.ebay.com/itm/1969-1990-C...53.m1438.l2649

one from Summit, lots of different oversizes available.

https://www.summitracing.com/parts/fem-csmhp727-300

These kits any good?

Was planning a DIY job except the balancing will have to go out I am guessing.

derekderek

If you're getting Pistons, definitely get forged pistons. If you're doing that, definitely bored out to 30 over. 20 is a very uncommon size and very hard to find pistons for. I have an 010 over 454 at home and that's even worse. But I am gonna change a couple of rods and put another crankshaft in it and see how it goes.

ddawson

From Summit
Approximate compression ratio 11.66:1 with a 116.9cc head.

If you have 100cc heads that's not going to work.

calwldlife

i shouldn't be surprised that now a days kits are avail.
still,
a lot to be considered and parts ain't just parts.
do it right.
a little more up front cost will benefit you later.
you will need machining.
makes or breaks a build.
piston material have different clearence
needs for heat expansion.
as do rings, plus angle of hone hatches.
if stock is the goal, then slap it together like gm did.
your money

derekderek

Also, compression ratio. 9.5 to 10.5. 30cc dome will work with 118cc heads. Those kits look like a collection of mid-grade parts at best. Buy the Pistons you and your machinist decide on. Same with bearings, rings, cam. Splurge on tie-bar roller lifters. They have spent 50 years refining cam profiles since these beasties were built. Used to be hard to get 1hp per inch. Now it is hard NOT to.

cv67

PAW practially lived there back in the day their kits were crap somewhere got an old catalog. lol

derekderek

Find a performance engine builder in your area. PM Doorgunner. he is a cunas gearhead his whole life. you are about 100 miles from NOLA, he will probably be able to point you to somebody. The bores need to fit the pistons. you don't buy pistons cuz the bores are a certain size. you get pistons the size you need for the bores to clean up, then you bore and hone until the clearance is correct for that type of piston...

Sigforty

Jebbysan

As stated the Fed Mog kit is for open chamber heads........but as far as kits go.....that is a damn good one for a meat and potatoes street build......
Here is the one I would get:

https://www.summitracing.com/parts/f...make/chevrolet

I had a 440 inch 427/400 a few years back with 10.25 to 1 TRW pistons in it and it ran great! It had a mild comp 268h cam in it too......miss that car......drive it anywhere.

Jebby

20mercury

Yes, know Doorgunner, great guy! And used to live in Baton Rouge for 27 years so heard of Womack's many times but never was a car nut then.

I would like to build the 427 myself but obviously need help with machine work and head rebuilds. Built beaucoup outboard motor blocks but never a V8.

About 1 hr from Baton Rouge now, Much thanks for the tip, I think I will call up Womack's and see what Remy says.

Engine is original L68, LQ stamp, plus have original heads, supposedly bored .020 over, have not miked the bores yet and was magna fluxed good.

Just want a Sunday afternoon cruiser so OEM performance quite ok with me.

Know gearheads in New Orleans, BR and Lafayette for shop advice. But have not talked with them yet. But I am thinking Womack's might be one of the best in Louisiana, thoughts?

derekderek

What are your head casting numbers?

20mercury

These are the original heads
3931063

And were apparently used in the 390hp and the 400hp, 10.25:1 compression.

(For OEM, I think these go with flat top pistons? maybe?)

derekderek

101cc semi-bathtub closed chambers. Flat pistons will go about 9 to 1. Ok, this is a basket case engine? So you know nothing about the heads. Get a valve spring compressor. Disassemble the valves and see how the guides are. If you can wiggle the valves around, I would think about starting with a different set of heads.