70 cast iron intake on a healthy 455 street motor
 

i purchased a used 455 +060, that i am going to put in my 69 firebird. I do not have all the specs, but by the dial indicator it has about a 580 net lift ultradyne street solid roller cam, # 15 heads that have had screw in studs and 1.65 sharpe rockers on it. I have had it running on my stand it its a snotty healthy little motor. zero decked, trws, main studs, been done failry well especially for when it was originally built in early 2000s. Currently has a performer rpm holley on it, but... i would like to keep it stock looking, and am considering a 69 intake and qjet, or a 69 intake and an adapter and a holley. I know everyone hates on the rpms any way, but aside from the weight savings, what am i giving up?
should be mostly street, about 450 hp lets say and a three pedal car with 323s in it.

70 cast iron intake on a healthy 455 street motor
 

Should be doable. https://uploads.tapatalk-cdn.com/202...a0eb83e3f9.jpg
Just did this Sunday. Automatic though. Car has run 11.80’s with better air and lighter driver.

461 #62 heads dished pistons. 9.8:1 car. Th350 3.73 gears. Car has G60-15 now. Ran 11’s with 1.75 60’ with bald radial TA’s

https://youtu.be/CttiVw7I35U


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Nice Dave> thats a big heavy car too, and street tires? if i run 12 anything i will do cart wheels. have the heads been ported alot? what kind of cam?

Test it with the Performer RPM intake first then after the change.


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With a ported iron intake it may run better.

We've had good results with the RPM.

Heads ported to 240cfm. Intake home ported a little by my son. Cam is HR 230/236 .510/.521. Has 1.65 rockers now. So more like .550/.570. 112 lsa


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Is the center divider cut down on the RPM? What about port matched?

SD does a great port job on stock intakes.

Just freshened my 70' 455 a few months ago. 9.7-1 comp,stock port matched 70' iron intake,RA4 sized HFT cam,rhoads lifters,Cliff Qjet, #64 heads 254 cfm on the intake,1 3/4" headers. Dynoed 491 HP @ 5200 ,,, 570 lb trq. A stock iron intake is very capable.

I took a 4 hole aluminum spacer and took out the material, front to back between two holes. Cut it in half so to speak, then made a little notch between the secondaries so I did not have to cut on the RPM. Worked pretty well.

We've also had good results with rpm on our 406 (runs 11.4s), building a 462 that'll also run one as well (although might test a couple different intakes if i dyno it)

Yes, I was also here to say you should send that intake to Dave at SD and have him give it a good working over.

Killer intake that looks stock, if you can't run well into the 12s something is wrong.

Ask Jim Hand about stock intakes....

Jeff, if it turns out your not going to stay with those #15 heads let me know as I will buy them from you.

I go either way. Nothing wrong with the stock intakes. With a little work they are pretty good.

Couple 455's I did. First one was a 463 and 10.2:1, had Edelbrock round ports that flowed 330 cfm and a 254/262 hydraulic roller. Dyno'd with a few different intakes on it, stock, victor, RPM air gap and a couple different carb spacers. This particular engine made best power with the RPM and a 1" open spacer under the carb.
Besides that, I'm not a fan of putting iron intakes on engines with aluminum heads anyway, so if a stock intake does well on the dyno I just go for a RAIV/HO intake.

Another stock intake on the last 455 I did was a 455HO with 197 Round ports that flowed 280 cfm, 239/243 hydraulic roller and 9.98:1 compression. Didn't try different intakes on this one because it was a stock appearing build so it got the original aluminum HO intake. It made 507/571 on the dyno through a set of stock RA manifolds. They work pretty well.

As a comparison among stock intakes, on my own RAIII 400 I've raced the car extensively for more than 2 decades with it's original iron intake. 4 years ago I swapped on a repop RAIV intake and have been racing the car since. The car runs identical with no discernable change in ET or MPH. Virtually the same design intakes so I wasn't expecting a change, other than maybe the complaints from others of the port issues on repop stuff, but my testing never showed any difference.

I don't think you could go wrong with what ever you choose. The biggest benefit with the stock intakes is the stock parts like RA air cleaners and carb linkage fit like they are supposed to without the need to modify things.

Picture of Jim Hand's engine with a Edelbrock Performer RPM intake....

https://pontiacstreetperformance.com...ackcoldair.jpg

Painted to resemble factory. With the RPM intake it produced one of his fasted runs with 11.51 @ 115.42 mph. 4070 lbs race weight.

His average from 4 different outings with different intake combinations during 2005-2006:

1/4 mile ET= 11.58 sec
1/4 mile MPH= 115.29


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x3 for SD to port the stock intake. i ran a 69 SD ported intake on a 467 stroker with OF cam & stock e-heads & a cliff built q-jet, car did 11.2-11.3 with traction issues at 121-123+mph.

i sold the iron intake to a member here a couple years ago & now run a 72 HO aluminum SD ported intake that runs the same times, so the ~25-30lbs weight savings isnt that big of a deal in the quarter mile. & stock intakes fit under lower hoods & throttle cables & chokes fit much better.

Hi Steve, I'm also confident that Mr. Hands fastest time ever was with an RPM.... and a Holley carburetor.

That's what I remember reading from eons ago. Some of the dyno numbers I've seen playing with that stuff favors in that direction as well on the mild 455's (500hp) I've seen.

Something I'd like to do sometime is take a bigger engine with more HP and see what the differences are, but usually the bigger victor or single plane style intakes start to show their worth at that point.