Ram Air IV versus 455 HO

[DaJudge]

Although rare, you could get a 455HO in a 70 Judge. Late model year introduction. I agree I don't know why they did'nt put a 12 -bolt under RA IV cars . A 70 455HO had standard d-port heads (64) and a cast intake. The 71 455 HO had round port heads and an aluminum intake (painted engine color). 4 speed 455 cars in 70 and 71 used the 068 or RA III cam. The 71 455 HO was closer to a RA IV but for performance and a great lumpy idle (527 lift cam) I'll take a IV car all day long.

[Belair62]

455HO is probably comparable to an LS5...

[Chevy454]

From what little Poncho exposure I've had, I tend to lean towards the 455HO. In Pure Stock competition the quickest Ponchos aren't the RAIV, but the RAII's and the 4550HO's. Granted, the IV's run well, but I put more faith in the II or HO combos as a whole...

[SuperCars]

This is all good feedback. I think Rob has good input from pure stock competition. Aside from lower compression, what I glean out of this is the 71 455 HO with more displacement and large round port heads had a lot going for it. Kind've like the 71 LS6 Vette, had to say that for Belair.

The RA IV's are great, and I'm not knocking them as I own a 69 and 70. But just quite surprised that Pontiac Engineers only felt a 10 bolt was needed, and that translates to performance in a round about way. The 71 455 HO W/ round port heads, and Pontiac engineers putting a 12 Bolt behind it would give me the impression that was their top performance drive train combo. Just my opinion.

[Belair62]

Didn't the 455 have a silly amount of torque ?? 500 or so...what is the diff between BOP 10 bolt and Chevrolet ?

[StealthBird]

The RAIV cam was the first computer designed camshaft in the industry. It was so effective, the camshaft is still widely used even today in Pontiac rebuilds, even with 35+ years of aftermarket cam grind technology available. Besides, we don't know any better.

The predecessor to the 1969 RAIV was the 1968-1/2 RAII. The RAII was basically a RAIV, but without the RAIV 1.65 high lift rocker arms, and without the nifty RAIV two-piece aluminum intake. On paper, the RAIV was a stronger combo.

But Jim Mino's 1968 RAII Firebirds seem to tell a different story. There has been a lot of speculation as to why the RAIV doesn't seem to do as well as the RAII and 455HO in the shootouts. In all honesty, I firmly believe that no one has really taken a RAIV to the same level that Mino took his RAII Firebird (or Jensen with his 455HO car). Those guys had a firm understanding of the Pontiac drivetrain, head flow, etc., and spent a great deal of time and effort assembling their combos. It appeared as if they were cheating, but they weren't. It was hard to believe a little 400, rated at a measly 340 hp, or a low compression 455 rated at 335 hp, could beat up on on so many high compression, big cube, solid lifter cars, 400 + hp cars, but they did. Mino's 68 Firebird was a lightweight, and so was Jensen's GT-37, but not "cheater" lightweight. They just found cars that were originally ordered in a street racer way. Jim Mino did a thorough teardown of his RAII a few years ago for a magazine, and showed every conceivable part of his 400 to the cameras. It was absoltely bone stock, unported, unmolested. He just assembled the engine with great care.

Pontiac 400's and 455's are low revving combos. They were so effective on the street because most street races lasted about 5-10 seconds, and during that time a person cannot take advantage of a 6000 + redline. Pontiacs focused on a broad torque curve rather than peak hp, and that made for a great street racer.

[Chevy454]

Hey Mike! Talk about your good running Ponchos! I'd still love to see that 'Bird of yours in action! But only if I get a "spot"!

Pete can jump in here if this is wrong, but I *believe* the Glasgo's have a '70 IV TA that they run at the PS events. If I'm not mistaken, it's in the high 12-range, and looks KILLER. One of Minos old RAII 'Birds is running PS with us, as well as another RAII 'Bird. I was sandwiched between these 2 cars in Stanton last year with my 12.47. And Jensen's HO car is sleeper if there ever was one...but you'd better choke up if you're gonna tangle with that T-37! Hard to go wrong with any of those packages.

[yellowjudge]

Hi, the 71 455 HO TA only received a 10 bolt, 3:08,42,73 ratios. I think the 455 H.O. great street mtr, just does not have the mystique of the RAIV. I have both, the H.O> a better cruising car.

[Charley Lillard]

The Pontiac 10 bolt is stronger than a Chevy 10 bolt. Might have 10 bolts but it is better.

[442w30]

[ QUOTE ]
From what little Poncho exposure I've had, I tend to lean towards the 455HO. In Pure Stock competition the quickest Ponchos aren't the RAIV, but the RAII's and the 4550HO's.

[/ QUOTE ]

Rob, I think you're confusing a few engines.

I am not sure ANY 455 1970 Poncho has run in the races where I see you race. These 1970 cars may be called 455HO in Pontiac circles, but not on the car. It always says "455 cid" and if you want to get picky, it's not a real HO car. They have nothing in common with the 455HO introduced the next year, which was basically a RAIV 455 but with low compression. The regular 455 was still available, and it received the same "cid" decals like in 1970. True HO cars received "455 HO" decals for 1971-72.

They made them in numbers marginally greater than 1969-70 RAIV GTOs, but when you factor the couple thousand T/As built, they are MUCH more common. I would not discount a RAIV just yet.