pontiac 461

[sameoldthang01]

building a pontiac 461 zero decked with butler performance lower end 4.25 , 6.800 rods. The quench area would be about .038 and I have bought a set of edelbrock 61579 heads 87cc. milling down to 79cc with a static compression of 10.75-1 . Do you think these heads are good enough flow wise to bolt onto the block or should I get some porting done? A bare head isn't an option in todays state of affairs and won't be available till May 2022.

[mag2555]

Out of the box they flow Intake wise about about 268 to 275 cfm@28".
Depending on how you have it Camed and Carbed at the low end of the flow rate I posted about the motor can make 525 hp.

A flow rate of 275 could make you 565 hp if everything complements each other.

With the minimum port area these heads have and your 461 cid this could mean peak hp taking place in the ball park of 5500 rpm.
Drivability with the stock out of the box minimum port area should be very good even with only 3.23 rear gears!

[sameoldthang01]

3.55 gear. I planned on using a stock cast iron intake with an 750-800 qjet. The distributor is recurved and all in at 2800 rpm with a 10 degree limit bushing installed. Turbo 400 could I use my stock converter 1600 stall?

I havent picked a cam yet that will be in the following month but I plugged in a 73 number and my dynamic compression was 8.0 . Any cam suggestions would be great and will be using a flat tappet with rhodes lifters if needed.

[amc fan]

Ram Air IV cam specs 230/240 @.050 .469 lift or something more modern with tighter centerlines. I think original Ram Air had 113-114 centerlines.

[mag2555]

You should forget about porting the heads since your going to run the factory intake, it will just be a waste of money, also the factory manifold will limit the HP back to no more then 460 with the Cam I bet your concedering running.

[Walter R. Malik]

building a pontiac 461 zero decked with butler performance lower end 4.25 , 6.800 rods. The quench area would be about .038 and I have bought a set of edelbrock 61579 heads 87cc. milling down to 79cc with a static compression of 10.75-1 . Do you think these heads are good enough flow wise to bolt onto the block or should I get some porting done? A bare head isn't an option in todays state of affairs and won't be available till May 2022.

I have built a 461 Pontiac with only 9.75/1 compression and Edelbrock "D" port heads. The heads were simply "bowl ported" and the engine used a Professional Products single plane, fuel injected intake with their hardware and FAST port injected software.
It is a 1975 Firebird with a 4 speed 3.55/1 gears; "knock off" cast iron exhausts.
Hydraulic roller cam ... 231/239 @.050" - .560"/.570" valve lift - 112 separation.

That car is one of the most "fun to drive" street cars in which I have ever been involved.

[mt-engines]

building a pontiac 461 zero decked with butler performance lower end 4.25 , 6.800 rods. The quench area would be about .038 and I have bought a set of edelbrock 61579 heads 87cc. milling down to 79cc with a static compression of 10.75-1 . Do you think these heads are good enough flow wise to bolt onto the block or should I get some porting done? A bare head isn't an option in todays state of affairs and won't be available till May 2022.

I have built a 461 Pontiac with only 9.75/1 compression and Edelbrock "D" port heads. The heads were simply "bowl ported" and the engine used a Professional Products single plane, fuel injected intake with their hardware and FAST port injected software.
It is a 1975 Firebird with a 4 speed 3.55/1 gears; "knock off" cast iron exhausts.
Hydraulic roller cam ... 231/239 @.050" - .560"/.570" valve lift - 112 separation.

That car is one of the most "fun to drive" street cars in which I have ever been involved.

Sounds Iike a rush of adrenaline.
How was the transient response?

[sameoldthang01]

I appreciate all the feedback. 450hp in this car will be just a beast! Besides the factory intake , what intake would you choose? Will the stock 1600stall converter work ok? Also, what rockers would you suggest? I would like to use the original looking dripper chrome valve covers for a stealth look and roller rockers might cause fitment issues but I could probably use a spacer?

[Walter R. Malik]

I have built a 461 Pontiac with only 9.75/1 compression and Edelbrock "D" port heads. The heads were simply "bowl ported" and the engine used a Professional Products single plane, fuel injected intake with their hardware and FAST port injected software.
It is a 1975 Firebird with a 4 speed 3.55/1 gears; "knock off" cast iron exhausts.
Hydraulic roller cam ... 231/239 @.050" - .560"/.570" valve lift - 112 separation.

That car is one of the most "fun to drive" street cars in which I have ever been involved.

Sounds Iike a rush of adrenaline.
How was the transient response?

GREAT ... at every throttle opening; even in a higher gear at low RPM. It detonates there though when you try to "lug" it.
The best thing is that it can run on REGULAR 89 octane gasoline with an educated driver who isn't to lazy to shift.

[tjs44]

You can use factory valve covers WITHOUT the drippers with the thick gaskets with H&S 1.65 rockers with no issue up too .660 lift.Tom

[Walter R. Malik]

I appreciate all the feedback. 450hp in this car will be just a beast! Besides the factory intake , what intake would you choose? Will the stock 1600stall converter work ok? Also, what rockers would you suggest? I would like to use the original looking dripper chrome valve covers for a stealth look and roller rockers might cause fitment issues but I could probably use a spacer?

For the first 3 months, this engine had a stock Iron intake and Quadrajet; just rejetted. At first, the owner didn't want to take the chance that his shaker hood would not fit. Then it was fitted with an "Atomic" throttle body from MSD with the stock intake but, he did not like how it drove under normal conditions so, the single plane intake with fuel injection hardware was fitted using the FAST fuel injection software.

You can tune almost every part of that fuel injection system and after a couple months of driving and tuning ... it became an absolute fun car to drive.

Harland Sharp rockers for a Ford 351W, 7/16" stud at 1.6/1 ratio were used and fit perfectly. Fitting under stock non-dripper valve covers.
Convertor "stall" depends upon the camshaft used.

I think SPEEDMASTER sells a copy of the Professional Products intake manifold.

[sameoldthang01]

Even now with the stock YS engine with 10.75 compression i run a mix of 93 octane and 110. 12 gallon 93 and 6 of 110.

[mag2555]

The YS coded motors never had a true 10.75 combo, they where all no mote then 10.25.

The factory always over rated the compression by at least.25!

If you had the high output motor with the 068 Cam instead of the 067 you have there would be no issue with running 91 octane.

[tjs44]

Not sure where you are,with our Calif crap gas I have been able to run 10.25 with Alu heads with our 91.Tom

[amc fan]

If the Edelbrock heads use Pontiac Rockers you can use AMC, Pontiac, or SBF Windsor roller rockers . then you have a choice of 1.5,1.6,1.65,or 1.7 roller rockers . So a cam with .469 lift with 1.5 rocker , .532 with 1.7 rockers. Look at Summit I think they have Pontiac aluminum intakes.