Ram Air IV versus 455 HO

[GTO_DON]

bill, your right that the 1.65's are the same size, BUT, because of the pitch of the rocker they will hit the valve covers! RAM AIR IV'S ABSOLUTLY TAKE THE THICKER GASKET! HAS ITS OWN PART NUMBER. look it up,its in the service manual..

[supergonzo]

maybe this will clear it up. I have 2 RAIV's always used the RAIV gaskets and never noticed they were any different.

[DaJudge]

Supergonzo, I guess I will throw out the two NOS sets I have since you say they don't exist, they are infact almost a 1/4 inch thick and carry a different part number. A lot of Poncho people don't know that the IV's valve cover gaskets are thicker, go figure. They also used longer valve cover bolts. The valve cover gasket part number is 9797580 and the bolt part number is 9784378.

[supergonzo]

heres another one
The rocker on far left is full roller rocker, then a roller tip rocker , then a 1.65 rocker , then a 1.5 rocker.
Can you see any size difference between the 1.5 and the 1.65??

You could be right, but I never measured the difference in gaskets, but The rockers never hit the valve covers either way. As you can see the 1.5 and the 1.65's are identical in size.

[DaJudge]

The rockers look the same but the ratio / geometry is different, the IV's also used longer pushrod and a special anti-pump up lifter. Having owned both a 455HO and a RA IV car not many engines have a better sound at idle, except for maybe a solid lift 427 Chevy

[Chevy454]

[ QUOTE ]
From talking to SuperStock guys, those Ponchos seem to do things kind of bassackwards of a Chevy.

As far as what makes them go or special tricks?? Most engines regardless of brand respond to mostly the same things...which is the right combination of parts. And careful building techniques, I am not sure what you guys think makes an engine tick. They all are just blocks, heads, intakes & exhaust and camshaft. Air pumps if you will, the more efficient you can make any brand the better.

[/ QUOTE ]

I'm a page late, but better than never I guess. What I meant by "bassackwards" was that from what I've read and what the Poncho racers have told me is that in the Stock/SuperStock ranks have to take a different approach than you would with a Chevy. With a Chevy you can let the engine accellerate the car, which gives you the "mechanical advantage" of running your typical loose race converter with some steep gears out back...quite the opposite with the Pontiacs. The Pontiac engines don't like to accellerate as well, so they've got to get the revs up and "hang them up", as they say, using a tight converter and geared down out back. Therein lies the problem, as with most cars you run 5.13s or whatever with a loose converter, and you gain a mechanical advantage with that...you lose some of that on the Pontiacs because of the converter/gear setup.

[Steve_Hoog]

If you have ever raced dirt bikes, maybe this will work for comparison. Small block = 125, Pontiac = 250, Big Block = 500. A Pontiac is more like a Big Block, but there are still differences.

Pontiacs definitely love a lot of fuel.

[supergonzo]

Yup, you right Rob, Chevy's you can gear to the track better. Because the power is at High Rpm's where the heads flow air like nobody's business. Pontiacs have much more of a street friendly hi-torque type of power band, So tighter converters and more street friendly gears work better.
Rob that car of yours is awesome, BTW...Hope to see you in July

All of this is related to ORIGINAL stroke and crank journal size, of which most Pontiac racers now use a smaller 400 3" main bearing size and aluminum rods which bring the disparity of Rev-ability much closer.

[StealthBird]

[ QUOTE ]
I think the 68/9 birds would of been quicker than GTOs. I have a 69 raiv TA, it seems like it is faster than my 70 raiv judge.

[/ QUOTE ]

This was the reason that Pontiac placed a throttle stop on all 1967-1969 Firebird 400's. They didn't want the Firebird outrunning the GTO.

[Chevy454]

A factory bracket car?? Wow, Pontiac really WAS ahead of the game!