[joeg]

Finally got her started!
A major goal accomplished, now it's time to get down to details..

[Engine-Ear]

Excellent, joeg!

[Teej]

Ah yes..the classic 421 2bb..... Ha It is funny when you think about it though, that's basically what it is,if you can keep your foot out of it. (or install block off plates...). Most people hear Tri-power and assume you'll get crappy mileage.

Great job Joeg, I'll bet you are stoked. Keep up the good work and let us know how you wring it out...

[joeg]

Progress!! Just about done with engine compartment, passenger side wheel tub next. Unfortunately I have to repaint both front fenders, the wind caught them a few weeks ago blew them over and scratched them.
As you can see I have installed the new style cruise controller on the drivers side wheel tub, integrated with the original 66 cruise unit...
If I could only get my trans pan to stop leaking, two gaskets and it still leaks..

[66bonne]

That is friggin' beautiful !! Nice job.

Jim

[SD421]

Originally Posted by joeg

Started assembling my 421HO for my 66' YK Bonnie but now my central air has died, the assembly is delayed for the next couple of few weeks. Dang It!!!

Anyway, thought I would share some pictures.

New Pistons .030 over.
Crank mains .010 under
Crank rods .010 under
068 cam
Original 093 heads with SS inserts and valves.

Great thread but Im confused. You installed 0.030 over pistons for a 428 yet a 0.030 over 421 would be a standard 4.12" 428 bore. So the 421 was bored 0.060 over??

[65WJ]

Originally Posted by joeg

Speed Pro L-2257F 30 = 428 pistons
Heads done by Borowski Race Enterprises, Rockdale, Il

Originally Posted by SD421

Great thread but Im confused. You installed 0.030 over pistons for a 428 yet a 0.030 over 421 would be a standard 4.12" 428 bore. So the 421 was bored 0.060 over??

Translated .030 over 421 (4.0965 iirc) = Standard 428 pistons. Not sure where you read .030 over 428

patrick

[joeg]

Sorry for the confusion the Speed pro pistons are for a 428 .030 over for a bore size of 4.150. The 421 was bored .060 over.

Originally Posted by SD421

Great thread but Im confused. You installed 0.030 over pistons for a 428 yet a 0.030 over 421 would be a standard 4.12" 428 bore. So the 421 was bored 0.060 over??

[SD421]

Originally Posted by joeg

Sorry for the confusion the Speed pro pistons are for a 428 .030 over for a bore size of 4.150. The 421 was bored .060 over.

Joeg,

Whew! Because 65WJ (Patrick) had me looking thru your posts again trying to find that Speed Pro Part #!!! lol

Im rebuilding my 1966 YH 421 motor and I forked out $448 for the Probe 4.125" (428 .005" over) forged pistons. It is too bad that the 421 piston is hard to come by. So I'll be right at 427.65 cu in.

What year is your motor because in your first post I dont see the date stamp by the distributor hole. Here is a pic of mine. A186 ( Jan 18, 1966)

Great thread BTW

-Don

[65WJ]

Originally Posted by SD421

Joeg,

Whew! Because 65WJ (Patrick) had me looking thru your posts again trying to find that Speed Pro Part #!!! lol

Im rebuilding my 1966 YH 421 motor and I forked out $448 for the Probe 4.125" (428 .005" over) forged pistons. It is too bad that the 421 piston is hard to come by. So I'll be right at 427.65 cu in.

What year is your motor because in your first post I dont see the date stamp by the distributor hole. Here is a pic of mine. A186 ( Jan 18, 1966)

Great thread BTW

-Don

sorry Don
when he first posted this I thought for sure it was just a .030 over
thanks Joe for the clarity.

patrick
ps mine is still standard bore

[SD421]

Originally Posted by 65WJ

sorry Don
when he first posted this I thought for sure it was just a .030 over
thanks Joe for the clarity.

patrick
ps mine is still standard bore

Patrick,
No worries, it just threw me a little. I was hoping to keep mine standard bore but there was 4-5 thousandths taper on the cylinder walls so I decided to rebuild the motor.
BTW what cam are you running & are you still using the original heads?
-Don

[65WJ]

The HO has a Melling SP-7 and 77 heads. However it blew both head gaskets long time ago. 1990 IIRC
Life, Marriage, tuition all in the way of putting back on road.

Bonneville (YH) from the reciepts I have still has the original cam (067) and 92 heads. this is my driver while other car gets put back together.
A HUGE thank you to Mike Nixon for fixing her back to where she just rides soooo nice. Thank You again Mike.

patrick

[joeg]

Don,

That's ok sometimes I get a little excited when I enter posts, I can't tell what day and month because part of the date stamp got machined away when the factory drilled the tapped plug for the oil gallery. Obviously the cast for your motor and mine are a bit different. Trying to find pistons was a real chore for sure. I was really rattled about putting it back to factory specs or try to lower the compression with different heads and pistons. In my case it all worked out just fine, very happy with the results and it runs just fine on pump gas...

Joe

Originally Posted by SD421

Joeg,

Whew! Because 65WJ (Patrick) had me looking thru your posts again trying to find that Speed Pro Part #!!! lol

Im rebuilding my 1966 YH 421 motor and I forked out $448 for the Probe 4.125" (428 .005" over) forged pistons. It is too bad that the 421 piston is hard to come by. So I'll be right at 427.65 cu in.

What year is your motor because in your first post I dont see the date stamp by the distributor hole. Here is a pic of mine. A186 ( Jan 18, 1966)

Great thred BTW

-Don

[Ragtop Man]

What was the dish in the Probe 4.125 piston?

Looking for something in the -20 to -25 or so range... depending on a.) finding the new job and b.) what it pays lol.

Love the idea of a 4.125" piston so you can use the up to date Chevy ring packs, which seal really well and don't have a lot of friction.

[SD421]

Originally Posted by Ragtop Man

What was the dish in the Probe 4.125 piston?

Looking for something in the -20 to -25 or so range... depending on a.) finding the new job and b.) what it pays lol.

Love the idea of a 4.125" piston so you can use the up to date Chevy ring packs, which seal really well and don't have a lot of friction.

http://www.probeindustries.com/Ponti...ns_p/14474.htm

Its a flatop with 5.5 cc valve reliefs. IM using the 6x-4 heads (94cc)to give me around 9:2 to 1 compression

All the other makes have what you want BUT at a .030 over piston size. If Probe didnt make the piston in the size I needed I would have gone with Race Tec.

The Race Tec Piston is probably your best bet. The pistons would have to be custom made (dished) but for what I was quoted, $600 for a set of 8 including pins. Its worth it. B-Man went this route with Race Tec dished pistons.

[joeg]

Finally after a summer of patching fenders, wheel tubs and quite a bit of body work including converting Catalina fenders to look like Bonnie fenders that entailed quite a bit welding and sanding. I painted the entire front clip and I'm ready for final assembly. Wheel tubs installed, fenders installed and aligned, lower valance installed, GP grills installed and thanks to Deadhead 's input I modified a set of GP grills by removing the parking lights and grafting in additional egg crate sections. Pictures to follow tomorrow of my Grand-Ville. So I'm asking if anyone has installed a bumper on a 66', the service manual is not detailed as to the exact procedure for installation and alignment. I don't want to mess up my paint job!!! Any input would be appreciated. Maiden voyage coming soon after almost 5 years.....

[Engine-Ear]

Hey, Joe, thanks for the update.

[ho421]

Bring on the pics.

[joeg]

Here are the pictures as of Friday.

[joeg]

Pictures continued