1981 Bird resurrection!!

[Fbird]

gets better every day. Serious re-evaluation needed as crankshaft would not clean up...its dead. Project on hold to determine budget crisis of build as another $500 into a poorboy special is just not the intention.
On the good notes: done porting the heads! Simple job not really hogging stuff out. Kept the throat dia at 82% vavle head, flatten the floor, push the roof up and rework the "push rod buldge" gasket match to RAIV gasket. Exhaust take a little bit of hogging in the bowl and only minor floor and exit work.

 

[Fbird]

Neglected to apply the "hot-Rod Golden Rule of Finance".....take the budget you THINK you will need....multiply by 1.5 ...and you should be close!!! scored a new crank for $250 who would have thought it cost $180 to grind a crank...really????? so for $70 I have a 0000 crank...no work required instead of a .040 x .010 crank.....times have changed in the pontiac world...


GAME ON!

 

[Fbird]

welcome to the roller coaster!!!

 

[G72Zed]

Hey Fbird, sorry to hear about your bad luck man, that bites. Just wanted to chime in on your thread on the topic of CR/455 and porting some OEM Iron heads and what I found worked well. I'm no expert, but found some interesting things.

My buddy took his 400 and got it bored .040 over and bought a Butler 4.250 rotating assembly, (cast steel crank, 2618 piston) came out with 462 cubes with 9.25 cr.

He got me to port a set of virgin 1971 #96 heads along with the Performer dual plane intake and build a custom carb. In the end, the heads flowed 220 cfm up from the <190 ish stock, I did not dig in on the floor as I found it too fast to begin with, changed to a 45* seat instead of the 30*, a little roof work, softened the chamber and kept the large runner radius intact and about an 88-89% throat. Set the PR pinch accordingly, that took some work.

My customers goal-target (wish) was 425hp and 500tq, we made 458hp and 520tq with ease, pulled clean and hard right to 5,300rpm. I was impressed with what HP/TQ those heads could support, with only 220cfm @ .500 lift, it gave us 2.08 hp per cube, not hard to tell when an engine is under headed with small CSA's, but it uses everything up.

All dyno testing was done with exhaust manifolds and 2-1/2 pipe, no headers.....

I flowed the head as a unit as well with the full intake track, still moved 207.5 cfm, 94.3% of the bare head. I'm not a Pontiac guy, but I liked the port shape and how this 455 worked out, not often you have a combo only loose 12.5 cfm with the complete intake track bolted up, and with a dual plane at that.

Here's a spec sheet I used, you may have this already, but just in case.

Anyway, I hope your luck starts to change.

 

[Fbird]

the pushrod buldge is the death of a poncho. .985 is a good number to work with after that...BEWARE. Sounds about similar to results I had yrs ago....no actual numbers as it was only a 10" bench (30 yrs ago) but achieved 22% increase on intake and about 18% on exhaust IIRC. These heads i did a mild throat open , widened the floor to the short turn and opened up the bulge. I'ts a 455 that will only see 5200 rpm with a .513 lift cam so keeping some velocity and low lift characteristics were important. Only did a little unshrouding of the intake.....not wanting 90 cc heads from my #62's...lol

BTW looks very clean!

 

[G72Zed]

Thanks man, my first Pontiac Iron head port job as well, and Yes, I had to really pay attention to that P Pinch, man that took time. I had no idea it was that small, but, the Pontiac engineers knew what they needed.

I got to .997 on the bottom, and 1.012/1.020 in the mid-top, that was it for me, customer wanted to to go even further, I declined as I did not want to tube or epoxy it if I blew through the wall. It's in a nice street 1969 GTO with 200R4 auto and I think 3.55 gear.

The #96 heads only needed to be shaved .025 to get back to the coincidental 96cc chamber. Worked out great for 9.25 with an inverted dome piston from butler. .

 

[Fbird]

FINALLY....ready to start the clean up of the block for ASSEMBLY!!! Expectation of completed short block 10-2-2021

 

[Fbird]

yeah that changed......expect PARTS to be here by 10-10-21...FOR the shortblock. Once parts are in order on the bench,,,then starting the "finish clean"

 

[Fbird]

CRANSHAFT n bearings arrived TODAY!!!!

 

[Fbird]

all engine parts have arrived!!!