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Edelbrock STR 15 Cross Ram ?s

Posted By: RATKLR

Edelbrock STR 15 Cross Ram ?s - 11/27/12 07:27 PM

I have one of these that I thought about using until I read the dyno results posted by Fast68Plymouth some time ago.
My lid has the carbs facing forward, although I may change that.
Has anyone tried raising the manifold plenum instead of using carb spacers? I know about the damn mods Mopar suggests, but is there any other tricks to make this intake work as well a good single plane?
I like the look, but I'm not willing to go slower just to impress others.
Posted By: Redsled

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 03:27 AM

I run a STR 14 - 6 which is similar but different and had the same thought. A friend suggested I make a plenum spacer, so I did. I made it out of 1/2" 6 ply poplar plywood. The car liked it so I made a second one, stacked them, and ran it. It didn't like the second one. I suspect because there wasn't "enough motor" under the intake. I figure the spacer was worth a tenth. I think the plenum spacer works because the lid in the original configuration doesn't have enough roof over the runners. The air has to make a real sharp turn to go down them and carb spacers makes 2 sharp turns. Just my This is w/ 2 spacers,not 1 which I still run.

Attached picture 7485054-Newintakespacers.jpg
Posted By: old_racer

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 04:38 AM

Hi,
Damon Kuhn and diamond back engine has done alot of work on that intake for N/SS racing contact him, http://www.diamondbackengines.com
Russ
Posted By: MRMOPAR

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 04:48 AM

I ran an STR-15 with single 4bbl top back in the 1970s. I could never make it run as well as the TM-6 intake.

Hot Rod did an article on intakes for "B" engines. The STR-15 among them. You can see that info at the link below. (When you go to the link, it will open a popup window asking you to subscribe to HotRod - click that link, which will take you to another page but leave the original page open without the popup. Switch back to the original page to read the info). Its worth the read.

Mopar Intake Manifold Shootout, Part 2

they even gave flow numbers on the headw (Modern Cylinder Head CNC Edelbrock Performer RPM heads)
they used in the test....
Posted By: coronetville

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 02:52 PM

I run a str 15 staggered cross ram bottom with a 1.5 inch spacer with a homemade 4500 top plate. Works very good, but have not tried any thing else, for comparison
Posted By: 1OFNONE

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 03:43 PM

I second the motion for Damon at Diamondback !!! His info helped me alot. Not only with hp, but drivability also. I miss my STR-14 car.

Attached picture 7485568-CarPics030.jpg
Posted By: poppaj

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 06:11 PM

I did alot of work with this intake and there is an early version and a later version, The later had interchangable tops and the base is the better starting point. For under 500 cu.in. around 3/4" between plenium and top works well. Over 500" this intake is not a good performance choice. poppaj

Attached picture 7485740-IMG_5149.jpg
Posted By: RATKLR

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 08:22 PM

Thanks for the replies. The Hot Rod test is really good info,(both parts 1&2).
I can post some pictures, but mine is the "Cross Ram" style with both carbs facing forward. Throttle linkage is on the drivers side of both carbs.
Most testing I have read about have the carbs inline or Max Wedge style with both carb primaries towards the middle of the intake.
The motor is a 383 with a 440 crank, 11 to 1 pistons, 296-557 MP cam. The heads are some old Stage 4s ported by ?, and flow 280 @ .550 lift.
After reading that Hot Rod article maybe I should put the old DP4B back on. My cam is closer to that Part 1 test than the cam in part 2.
There are so many variables that effect the outcome, but several years ago Chrysler Power Magazine tested B engine intakes and the TM6 was best. It did have some port work though where the plenum meets the runners, which makes a big improvement.
Posted By: Steve1118

Re: Edelbrock STR 15 Cross Ram ?s - 12/02/12 08:30 PM

That intake was the wedge version of the "Rat Roaster" for Hemis. Those Rat Roasters were never as good as a cross ram, but with a 1" spacer between the lid and the bottom it really picked them up, especially with the inline Carter AFB lid, which was the most common. They also made crossram lids, and lids for the single Dominator.

Attached picture 7485978-RatRoaster.jpg
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