New Dyno numbers on 1970 trans am engine
 

Some people might remember that a few years ago I was having trouble with the engine in my 1970 Trans Am. The actual reason for the problem was I missed a shift. I don't need to go into the details. Let's just say that the engine was gone through and the necessary items that needed attention were taken care of. Some facts of the engine are it is a stroked 400 service replacement block to 433 cubes. the Ram Air IV (614 casting) heads were ported and a slightly bigger cam was installed. Also, Doug's headers were installed with a 1'7/8th primary and 3.5-inch collectors. Intake manifold was changed to an Edelbrock Performer RPM. The cam is an off the shelf Comp cam XE288HR version and had the engine dyn'd. Previously, the horsepower and torque were 535 TQ @3600 RPM and HP was 447@ 5000 through Ram Air IV exhaust manifolds. These results were with the 230/236 Comp cam @.50 HR112 and Ram Air IV repro Intake manifold. Heads were not ported. It has been three years since the incident took place and has been some adventure to get the engine running and dyno'd.

Here are the results:

That peak hp number of 481 looks high for stock RA4 heads.

He said port heads.


:)

DCI just ran a pair and made 495hp.

Remember the first two columns represent uncorrected numbers. The next two are corrected. Uncorrected Torque is 485, while corrected Torque is 513. Uncorrected horsepower is 481 and corrected Horsepower is 511. Also, this is not a 400. It is a stroked 433. Has a crank with 4.0-inch stroke and .030 overbore. Lastly, the heads are ported.

That is all kinds of cool! Very nice! Thanks for sharing the result!

30+ years ago, Slawco made my 48s do 550 HP (455+060) so 433 RA-IV doing as-posted here is low-risk port work.

Yes, a low-risk port job was done to preserve the 614 castings. I didn't want to run the risk of ending up with messed up heads like my previously purchased superduty number 16 heads. One of the previous owners really screwed up the port job to the point that too much material was taken out of the bowl area and results in negatively affecting air flow. The result was 520 hp and 578 tq on my 496 in my 1973 Trans Am. This 433 RA IV puts out estentially (sp) the same horsepower as my SD 496. I don't want to go through the hassel and expense of getting the SD heads fixed.

Is this corrected? It says those numbers are uncorrected.

Stan

Yes. I stand corrected. I forgot the only numbers I had before the missed shift incident. Remember that was 10 years ago. Same jerk dyno operator my engine builder likes to use. The dyno owner spent money on a new engine dyno and software. Finally got the corrected numbers I was looking for. This was the last time using this dyno with this guy. My engine builder has to find a new dyno guy.

Very nice!

What is the compression and head flow of the new combination?

Cool! I have a 4" billet crank Pontiac Dude got me along with the 4.21 in my 500 before we had forged cranks with the intention to put my RAIV 614 SRs on it and go in my 65 GTO stick car project. Figured a 455+ with them would break crap with a stick! Paul has the heads right now . They were pocket cleaned up and port matched per NMCA rules.

Compression is 10 to 1. The heads were not measured. I told my engine builder I would of liked 260 cfm. Using the rule of 2 to 1, I think it is there. My engine builder thought there was another 10 hp in it. Thanks.

Hope you get the numbers you want.

My chambers with flat non tuliped valves are 69cc. Flowed around 250-255 on the intake 85% on the exhaust of that. Ran better with a reverse split cam. Most of the RAIV Stocker and SS guys run single patterns.

Skip.
How much reverse split did you run?

I am just playing with some math, and for 250 cfm int and 212.5 cfm exh I get around 5 degrees.

Thanks,
Stan

I initially tried a "normal split" 288.296 UD HFT on a 108 LS, a 304/312 UD HFT in a 112 and had the IC in 2 different spots 4 degrees apart some time/mph. A 288/292 SFT UD to get closer to a single pattern, same times. Ended up saying what the heck lets go way different 292/286 Comp 242/236 @ 0.050 .HFT on a 110 was the ticket . but the car had to run through exhaust 3" H,mufflers but 2.5 tailpipes per class restriction. The car did like a 1 3/4" header vs the 2" also. The 304/312 did pick up a lot uncorked.

John Schloe's 69 NHRA stocker when he ran the RAIV was a Comp 274/274 @ 0.050! I had no V-P to even try that one when I got a copy of it, even if it would fit it would not make vacuum for the idle rule in NMCA! John Angeles ran a single pattern in his SS car he told me.

I love when people state there heads flow numbers, but with no lift number tacked on.

The OP told his head/ engine builder guy he wants 260 cfm, well at what the heck lift!?

A RA4 head reworked to flow 260 cfm at around .400” to .450” lift is way the hell different then a RA4 flowing 260 @ .650” lift.

I'm amazed at the amount of folks that think "porting" is a machine shop operation and every shop can perform the task. The RAIV is probably the most difficult head out there to get to work right. Sadly, because of its flow characteristics it causes even moderately experienced porters to keep removing metal to attempt to get them "right". There are way more screwed up ported IV heads out there than good ones. The saving grace is the majority of them end up on restorations that are rarely driven down the road.

I'm working on a W-31 engine that had the heads ported by the last shop. It looks like a five year old went at them with a Dremel. The good news, it's as hard to do damage with a Dremel as it is to find a measurable gain.

I have a basic single orifice flow bench, access to a Superflow 110, shops with the bigger Superflows. I quickly learned on an old D port #16 I am not a porter! I can make them look pretty though!

Steve my numbers were at .550!

Paul, I agree.

It’s hard to do harm with a Dremel tool , but then again I have seen the work of one SBC guy where he removed the whole bottom cut out of bowl with his Dremel thinking that’s what a bowl blend job was.

It must have taken him 6 hours of work with that tool and 12 Dremel grinding stones to do all 8 intake ports .

If a RA4 head has been messed up by hack porting it, yet flows lets say 245 to 250 cfm at .600” lift, then there’s a good chance it can still be saved if the motor there going to be used on can use the port area that 200 CC or so Intake port will end up being.