[Skip Fix]

But mine did not ping on the dyno yet still wanted more octane! Pushed a 3950lb TA to mid 12s @ 109 back when Jim Hands wagon was also just in the 12s.

[Skip Fix]

Tom S has probably had lots of various classic high HP Pontiac iron head motors on the street that get driven hard-ask him about 10:1+ on pump gas.

[PAUL K]

Originally Posted by SD455DJ

I have a complete '70 RAIV SR motor (.030 over) with cast rodes, uncut NOS RAIV heads (11/74 casting dates) that has 9.75 to 1 SCR. It's on an engine stand now and is the motor I used at the Pure Stock Drags in the late '90's and early '00's. It has the Crane RAIV blueprint cam as well and in a 4000 (+) lb Judge with a TH400 trans and stock 3.90 gears ran great on 93 unleaded, never pinged or detonated. It would slow down if I added race gas at the track. It was slow off the line (2.0 60 fts), but ran 13.50/60's at over 105 mph repeatedly.

With a real WW Factory RAIV engine with 11.0 to 1 SCR (Eagle forged rods, Ross forged pistons, Crane RAIV cam) it ran 12.80's at 109 mph. These motors need compression and race gas at the race track. The heads measured at 66 cc's, but were cut by the previous owner.

Dennis

Great info...thanks for sharing.

[Skip Fix]

My RAIV motor actually picked up way more with a Comp Magnum lobe 242/236 @ 0.050 on a 110 LS-but kind of a rowdy idle in a 400. That and smaller 1 3/4 headers got the car down in the 12 teens @ 110-111 mph all with 2.5" tailpipes per class rules. 1/4-1/3 race gas was enough to keep mph up and not drop HP with all the cams in the motor. After the 288/296 108 HFT swapped in a 304/312 on a 112 degreed at 110 IC for more V-P then 106 as UD suggested -same times. 288/292 SFT UD on a 110 -worse idle but pulled higher rpm.

[STEELCITYFIREBIRD]

...557 blocks don't not have them (valve chamfer @ top of bore)/ w/4bbl..FWIW.... irrelevant but just noting, here we have the best and worst 400 blocks

Originally Posted by steve25

All 400 , 428 and 455 4bbl motors have the intake air flow improving chamfer at the top if the bore , and even some 2 bbl blocks slipped off the assembly line with them, and yes the earlier blocks had them but not at the bore center.

In general add 2 CCs to your compression tally and when you do you will not be at 10.18 to one, and to top that off you can add in yet another 1.5 CCs for the total first and second compression ring land back volume that few seem to ever add into the compression math !

[SD455DJ]

Originally Posted by PAUL K

Great info...thanks for sharing.

Paul, My pleasure! This is an interesting thread.

Dennis

[Skip Fix]

It is always interesting to hear what other folks with RAIV motors run. Enjoyed meeting John Angeles and talking about his RAIV SS motor a couple of years ago when I was out with Tom S for the Donut Derelicts Saturday deal. Tom tossed me in one of his cars (Tempest) and said follow me! And I had to try and keep up!

[Boiler]

Thanks for the data point. We are still struggling with what to do with the SCR. I'm thinking 10 to 10.5. It would be nice to run pump gas but if it takes racing fuel to make the car run the way it should that may have to be the answer.

I have found two different RA IV cams which claim to be exact copies. There is the Blue print from Crane and a Melling SPC-8. Are they each true copies? One better than the other?

Originally Posted by SD455DJ

I have a complete '70 RAIV SR motor (.030 over) with cast rodes, uncut NOS RAIV heads (11/74 casting dates) that has 9.75 to 1 SCR. It's on an engine stand now and is the motor I used at the Pure Stock Drags in the late '90's and early '00's. It has the Crane RAIV blueprint cam as well and in a 4000 (+) lb Judge with a TH400 trans and stock 3.90 gears ran great on 93 unleaded, never pinged or detonated. It would slow down if I added race gas at the track. It was slow off the line (2.0 60 fts), but ran 13.50/60's at over 105 mph repeatedly.

With a real WW Factory RAIV engine with 11.0 to 1 SCR (Eagle forged rods, Ross forged pistons, Crane RAIV cam) it ran 12.80's at 109 mph. These motors need compression and race gas at the race track. The heads measured at 66 cc's, but were cut by the previous owner.

Dennis