472 storker with edelbrock str-15

[73rattler]

Hello all,wanting to see if anyone might have some ideas. I had this motor all biuldt up with the intent of running the edelbroke cross ram. I've had this intake for years,and wanted to run it. I've had the motor running and took it out for a test drive. For that short drive of about 5 miles it ran great. BUT now I have had problems with it fouling plug, getting alot of gas in the oil.
I had my engine biulder come out and look the motor over and help figure out what was going on..what he found was way too much gas getting in the oil and toold me to change oil and filter ,,need to go to hotter plugs and close the gap to no more than 30 thousands I did all this and it ran and sounded even better. BUT with only a sart up in the garage for a few minutes and pulled it out to load on the roll back it is starting to foul the plugs again and they are black.

The motor is a 472 c.i. roller cam, intake.544 exhaust .541 lobe sep. 110 roller rockers of 1.6 Indy heads. Had some issues with the intake with it bloing out between lid and bottom,,but I drilled to add 12 small allen head bolts all around intake so there is no more than 2 inches of space between each bolt. they are counter sunk under the carb bases. running QFT carb 600 double pumpers.

I have been thinking maybe too big of carbs and wondering about edelbrock 500's and also thought about reducing the plentum area. I been checking around on forums to see what others have done. My engine biulder wants me to do away with this intake and run a single four barrel but I really would like to make this work.

 

[silversedan]

call Damon Kuhn at Diamond Back engines in Texas, google Diamond Back Engines and you should find him , if not pm me and I'll get his no. he has done extensive work with that intake.

 

[lewtot184]

i'd get into those holleys first. maybe a power vavle issue, float level, fuel pressure,...? ignition curve could be a problem too. those intakes were actually designed around the 600/650 mech holleys. i wouldn't touch a 500 edelbrock with a ten foot pole.

 

[Meep-Meep]

That intake is a fuel distribution nightmare so you better get on a chassis dyno and be prepared to make drastic changes to the carbs. Not only jetting, but possibly air bleeds, emulsion tubes (metering blocks) and building dams in the plenum area. The old DC book has the modifications, which may be a good starting point. But for starters, I agree with Lew that you need to check the basics like float and PV. Another thing to consider, especially since you have so much excessive fuel, is that intake makes a pretty good bomb. One good backfire and the lid hits the hood (and hopefully not your face should you happen to be standing over it). Be careful!

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Oh, and you said 472 with a 15? If 440 based stroker then that would be a 14. 15 is for the low block.

 

[coloradodave]

Good Lew. I guess I don't have to worry about you stealing either one of mine....lol.

 

[73rattler]

Thanks to all that has written some subjustions. Silver sedan,,I came across Diamondback before I wrote this thread. I have it bookedmarked. What I have done so far prior to writting this thread is.. Changed the jets from 65 to 63 prim and 72 to 70 sec and changed the power valve from 6.5 to a 4.5 because of vacume reading. Engine sounded better but wouldn't drive to well....Put the car back into the garage and was pulling carbs off to put the orignal jets back in. THAT is when I found the hair line cracks next to the carb mount front and rear just in two spots. and found it not to be sealed up between the lid and bottom of the manifold.

Took the lid to my engine biulder and he told me to just jb weld the cracks since they was so minor and I mentioned about adding 6-32 allen head bolts all around the edges to fill in the large spaces between bolts. THAT alone took 12 bolts and there is no more that 2" of space between the larger bolts. A rubber fiber gasket and a thin coating of sealer . Doing that has streathin the lid as It doesn't flex anymore.

By the way I do have the direct connection racing manual book from 1975 with all the modications to these manifolds ..BUT I just looked threw it again before writing this and all the ones in the consering this manifold are for the single four barrel and inline dual four barrel and six pack,,,the one that shows the cross ram is the 426 max wedge and that is a different mainfold.


this is also a 400 low deck stroked out to a 472. I also changed the air bleeds too,,forgot to mentioned that when I changed the jets,,opened them up by four points. I'm going to recheck the poer valve to make sure they didn't get blown out when the car spit back threw the cards a couple of times when tring to start it when the engine biulder was here,,and also put the smaller jets back in and see how it response sine I have the intake sealed up.

 

[Jeff_383]

Go on Moparts and look up Lar_414. He has one on his 416 smallblock and with much tuning and trials, his works awesome. Pick his brain. He's a good guy.-Jeff

 

[73rattler]

OK..Had some improvements last night on good friday. After work I worked on the engine,,changed the primary jets from 65 down to 61. sec. from 72 down to 65 and changed the power vale from 4.5 back up to 6.5. changed the hoter plugs back to new regular plugs and set the timing at 36 degees. flote levels are good and fuel presure to around 4or 5.....Made a BIG differance,,no more eye watering smoke from the tail pipes. In fact I didn't notice any smoke. everything seems to be the way it's suppose to run. Might need a little more adjustments,,but for now it all seems to be good.