"Pontiac dropped the ball in 1970 by not having a 455 RAIV ready" This is correct/ Pontiac 455 HO motors were made after compression ratios had already dropped to 8.2 to one.
Even at this rating 455HO's are strong motors. The 1970 455's were not high performance motors. Pontiac of course got in one more shot in 1973 with the 455 Super Duty, which is the ultimate Pontiac 455 motor. And could run with any muscle car ever built. The exhaust manifolds on SD cars are quite good, among the best Pontiac ever produced, however the pipes went back to a crossflow muffler in front of the gas tank, that REALLY added alot of backpressure to the excellent 455SD heads trying to breathe. Similar to big block chevy muscle cars....un cork the exhaust and you made ALOT more power. 50HP is very accurate.
As for RAIV's 400's, They were mid 13 second cars straight off the showroom floor, if you knew how to re-curve the distributor, and reset the timing correctly. If you removed the cleverly designed factory removeable pre-heater crossover and used block off plates you got another 10th out of em'......How do I know?? I have 2 of them now, and run them frequently in pure stock condition on radial tires and they run low 13's to 13.00's depending upon track temperture. I regularly beat my LS6 70' Chevelle. Weight has alot to do with that though. Go look up any pure stock/factory stock drag results and you will see these cars all running close to 13.00's on bias ply tires!!
I am also the organizer of this years Northeast Factory Stock and FAST Drag race.
www.musclecarrace.com
Come out an see RAIV's as well as LS6's and HEMI's and alll the heavyweights do battle.
Anyone who has even looked at a set of Pontiac heads/intake and exhaust and compared RAIV parts and standard Pontiac performance parts would see an OBVIOUS difference.
As a side note. Both my 69 RAIV GTO's weigh 3700lbs
My 69 400 Firebird weighs 3450 lbs.
A 69' RAIV 400 Firebird or T/A properly tuned is a top performer. There is one that runs in pure stock classes running 12.70's again on bias ply tires.