[gobrdgo]

Hi everybody. Slowly gathering the bits for my build. 69 firebird. 455 two bolt , NOS rod kit from a PAW catalogue with Milodon rod bolts. 96 heads port work in progress. I’ll call it mild for now but but we are using a flow bench. I say we but my buddy s the one with the big brain. Bullet cam. 292 300 adv duration 520 lift 109 lobe separation. Gran prix long tube iron manifolds, Intake is 66 tri power Mr Boneski from the board is re working. 5 speed Doug Nash and long shifter, with a 9 inch posi 3.00 gears. Wheels are 15” radial tas on 15 inch rally’s. Cal trac rear springs. ( split leafs). Otherwise just a mechanical restoration. Whatcha think so far? I’ll be happy to get sideways and be in the 13s.

[Dave M]

Not sure the 109 lobe separation will work well with iron manifolds. But I’ll let people who are way smarter than me give their opinion on that.


Sent from my iPad using Tapatalk

[steve25]

I don’t know if you where intending to, but do not attempt to replace those rod bolts on your own.
They need to be done by a shop and then the big ends need to be checked for being round, and resized if need be.

You should look up Jim Taylor’s 421 tripower build article from the Sep 2013 issue of HHP where he gets 475 hp out of the motor.

He was running more compression then you are and headers, but you heads should flow better , and you have more CID.

The Cam Jim was running was a good amount bigger then yours, but this is what allowed that motor with iron heads to run a 10.6 to 1 compression.

Speaking of porting work , you should flow test and port those exh manifolds while your at it with the heads.

Intake flow wise from the porting work you should be looking for a minimum of 230 cfm@.500” lift, and 175 cfm @ .500” on the exh side, which should be easy with the exh ports in those 96 heads.

Keep careful track of the critical intake flow numbers at .200” lift.
You do not want to lose any of the stock flow numbers there with the porting work being done, in fact if the work is being done right you should pick up 8 to 10 cfm over stock.
Be sure to rework the center exh ports first to get the 175 and then go do the outer exh runners since they will take less work.
Here’s a shot of what a center exh port should look like.
Of importantance is to note that only the roof is raised and the upper side opened up some to match a stock metal exh gasket.
Do not gasket match the floor at the flange , and only polish the floor, do not remove any material but for the casting nub standing up in the center of the crown of the short turn in each exh port.

Connecting rod wise if you have a decent hand grinder, or even a bench type grinder you should remove a bunch of the unneeded mass on the small end of the cast Rods.
Weight removal way out there at the small end pays off in Spades in terms of less stress on the Rods and a motor that has increased performance just because that weight reduction allows it to rev faster.

[android 211]

The most popular budget street 455 build uses the RA IV cam. You can use the 1.5 rockers you already have which will knock off a few degrees. Advance it 4 degrees. Its got a wide LSA which will work with the cast manifolds better. You're using a stick shift so you don't need Rhoads lifters. What's Mellings call it in the catalog? SPC-8? You can order it from a local parts store. I'm using 96 heads on my 455. I have the 068 cam with 1.6 rockers. It has a very smooth idle. I have 1 5/8" headers. On the dyno it made 525 ft/lbs, at 3000 rpm 387 hp at 4400 rpm. After 4500 it was tapering off.

[gobrdgo]

Originally Posted by android 211

The most popular budget street 455 build uses the RA IV cam. You can use the 1.5 rockers you already have which will knock off a few degrees. Advance it 4 degrees. Its got a wide LSA which will work with the cast manifolds better. You're using a stick shift so you don't need Rhoads lifters. What's Mellings call it in the catalog? SPC-8? You can order it from a local parts store. I'm using 96 heads on my 455. I have the 068 cam with 1.6 rockers. It has a very smooth idle. I have 1 5/8" headers. On the dyno it made 525 ft/lbs, at 3000 rpm 387 hp at 4400 rpm. After 4500 it was tapering off.

. I already ordered the cam, and I have an 068 in the short block now lol. I suppose I can try headers down the road.

[gobrdgo]

[QUOTE=steve25;6263332]I don’t know if you where intending to, but do not attempt to replace those rod bolts on your own.
They need to be done by a shop and then the big ends need to be checked “.
I failed to mention they are already sized and fitted with the bolts from PAW.

[steve25]

Ok, PAW reman stuff has been known to be substandard at times, so when you have the rotating parts at the shop to get them balanced and have the pistons installed on the Rods have the shop re-check the Rod big ends.

And even before that check the Rod big ends for the bad news of too big of a chamfer at the parting line.

A proper resized Rod only needs a chamfer at the parting line equal to the thickness of a Human air.

Any more and you have the potential of Bearing problems taking place!

[Cliff R]

96 "D" port heads have pretty big combustion chambers. Even with zero deck height and a pretty thin head gasket you'll woln't have enough compression for that cam....IMHO. It will run OK, but expect low vacuum at idle, rough idle, stinky exhaust and a little lackluster at low rpm's.

Cams like that will "feel" really strong from about 3500-5000rpm's as they tend to pull very hard in the mid-range and narrow up the power curve considerably. Certainly it woln't be disappointing anyplace at WOT, but I would have had the cam pushed out on a 112 or even 114LSA to knock some overlap out of it, less reversion and help with the long branch exhaust manifolds......FWIW......