Home Car Stories One Owner 1970 PONTIAC GTO 455 HO- Mandeville, LA
1970 PONTIAC GTO 455 HO- Mandeville, LA PDF Print E-mail
Written by Double Dragon
Thursday, 23 October 2014 19:26

1970 PONTIAC GTO 455 HO- Mandeville, LA


Writing copyright D. S. Brown photography copyright owner of GTO

The 1970 Pontiac GTO carried forth the fantastic bodystyle that debuted for the 1968 model year and had remained virtually unchanged for 1969. In 1970 the headlights were now exposed and the grilles were shrunk in size but the front Endura bumper was still used. A new rear bumper contained rear lights that wrapped around to serve double duty as side markers. The basic body shape was much the same with additional 'muscle accent' creases above each of the wheelwells. Hidden from view the doors contained side impact beams, and the roof was reinforced to better withstand rollovers.

70 Pontiac GTO 455 HO mandeville la pass front

The big news for performance people was that for the 1970 model year General Motors lifted the cubic inch limit on intermediate musclecars. The GM divisions scrambled to find a suitable big block engine to stuff into their existing musclecars. For several years GM muscle needed something beyond the 400 cubic inch limit GM imposed during the 1960s. In order to do battle against Chrysler's 440 and 426 monsters and Ford's 428 and 429s GM needed a big cube engine set up with high performance cam, induction and exhaust.

70 pontiac gto 455 ho mandeville la front

Buick surprised everyone by hitting the mark better than the rest with the 455 Stage 1 which is still paired up in grudge matches against Hemis to this day. Oldsmobile already had some experience with 455 installations in their 'Hurst/ Olds' version of the 442. Olds was the first to release an official model with 455 cubic inches. Olds was inventive and used a technicality to allow an outside vendor (Hurst) to take responsibility for the presence of a 455 between the fenders of the Hurst/Olds 442s. Oldsmobile retained the Hurst standard of performance when they quickly whipped up a 455 W-30 for the 1970 model year. Chevrolet stunned everyone with one of the highest horsepower ratings in musclecar history for the LS6 454 Chevelle SS. John DeLorean had just shown up as Division manager after a wildly successful term as Pontiac Division manager during Pontiac's peak musclecar glory years. The 454 coup however really traces back to development work going on with Duntov and the Corvette and some back door COPO 427 Chevelles. DeLorean embraced the concept and let it hang out all the way.

70 pontiac gto 455 ho mandeville la side

DeLorean's absence from Pontiac triggered some changes. His opposition to a rear sway bar on the GTO was quickly amended for the 1970 model year which improved handling. Pontiac had been working on a Ram Air V in 1969 and this dedication to the concept of a high revving 400 engine carried forth for the 1970 model year. Would DeLorean have pushed for a high performance 455 if he was still there? We'll never know for sure, but we do know what did happen.

A 'D port' 455 was created from the 428 and made available for the GTO mainly it seems because it was possible to install a 455. Pontiac's performance focus stayed with the 400 Ram Air III and Ram Air IV engines. Pontiac's intent was that the 400 would carry the performance torch in 1970. As wild as the RA IV was, when the 1970 GTO was tested by HIGH PERFORMANCE CARS it was considered a good musclecar by mid 1960s standards but not sufficient to handle the new crop of muscle. The GTO relied on 6 inch wide 14 inch wheels and the 400. It was found lacking compared to 15 inch 7 wide rims and big blocks available in competing musclecars available for the 1970 model year.

70 pontiac GTO 455 HO mandeville la engine

The 455 HO Pontiac installed in a small number of 1970 GTOs was not a true HO in the sense of cam, induction or exhaust but was a low revving torque monster. The 1970 455 was intended to cater to the needs of the GTO owner who wanted good off the line performance along with A/C, power steering, power brakes, power windows and other power sucking weight adding options. Peak horsepower and revs were not part of the plan.

This particular GTO seems to fit some of the engineering projections for the 455. It is equipped with air conditioning, power steering, power brakes, automatic transmission, remote outside driver's rear view mirror, console, and a vinyl roof. The 455 can handle those accessories and the extra weight added to the car.

This GTO is painted with a subtle color combined with a tasteful interior color which accords with a magazine testers prediction that not all 1970 GTOs were going to be wild colored spoilered Judges with Ram Air and 4 speeds. They expected many buyers of the GTO to choose it simply because it was such a good looking car. Many 1970 GTOs went out the door equipped with creature comforts and painted in restrained color combinations like this low key car.

70 pontiac gto 455 ho mandeville la interior

Road tests from the day are variable. The quarter mile time didn't impress some magazines. Thomas McCahill wrung out a 1970 GTO convertible with a 455 and despite the aerodynamic disadvantage and extra weight of a convertible body he managed 134 MPH in a 455 GTO.

In 1971 the Ram Air IV equipment was loaded onto the 455 and a true round port HO was created and one of the fastest GTOs of all time resulted.

We know about he legend of the 1971 and 1972 455 H.O. but what about the 1970 455? Was it really such a disappointment? It seems that perceived performance versus the actual real life experience wasn't subject to such an extreme variance. By most accounts the 455 is actually a pretty fast car. It's just that the 1971 and 1972 version and later Super Duty versions of the 455 were such monsters they overshadow the lesser 'D port' 455s.

This is similar to the decades long stigma against the 1971 and 1972 GM musclecars which were dismissed because of lowered compression. The actual truth is that the cars looked nearly identical to the 1970 versions and for a driver without benefit of a quarter mile timing light it was very hard to feel much in the way of power loss. Gradually awareness of the extreme quickness of the 455 HO GTO from 1971 did a lot to alter this perception. So far, the 1970 455 is still subject to some prejudice but for a driver on the street the off the line response is fantastic.

The owner of this GTO tells us that this is an all original car except for one repaint many years ago. The car shows a mere 61,000 original miles. It was always garaged and has the original spare tire and jack, all original documentation including Protect-O-Plate, title, bill of sale, and PHP papers. In October the GTO was listed at a reduced price of $27,000.00 as a one family car.

70 pontiac GTO mandeville la rear

Last Updated ( Monday, 24 November 2014 10:07 )