Well here is my situation.

I have an 89 iroc with a flat top hyper piston 383, xfi 280 cam, t56 w/ 342 gears, 1 5/8 shorties into 3in flowmaster catback. currently no heads of intake.

I decided to quit messing around and ordered a set of AFR 195 comp port heads I got mine with 64cc chambers, l98 plug angle, larger diameter 1.50 springs and 7/16 rocker studs. Should be here in a few weeks.

I originally wanted to go with a miniram, 58mm tb and some 30 or 42lb injectors$$$$ I am now considering going with a vic jr efi or simular intake. A local speed shop makes a nice tb elbow and I'd use a 78mm ls1 tb. I spoke with Jerami at AFR and he said I'd lose a significant amount of low end over the miniram and I wouldn't see much if any gains. I have plans for a turbo setup in the distant future( twin mp t70's w/ 68ar ). I don't know how the miniram will handle boast at the 700+hp range. I understand the single plane setup will behave better under boast but I don't want it to be a bear on my na motor.

So I'd like some imput from the guys that have actual experiance with a simular setup. Thanks guys.

Some might argue different
https://www.thirdgen.org/forums/alte...iscussion.html

https://www.thirdgen.org/forums/post...492-post3.html

https://www.thirdgen.org/forums/tpi/...ject-xsp1.html

get yourself a Hurricane EFI Manifold, you can get them for less than 200 bucks brand new. They are hands down the best Single Plane manifold you can get. Better than Super Victors and Bowties, its been dyno proven on many occasions.

You have got a 383, they are going to have decent torque regardless of intake choice.

Will the bottom end hold up?

It's really easy to make twin chinese turbo 700+hp 383, really easy.

Not as easy keeping the crank from jumping out of the bottom of the block


On a boosted application, singleplane wins hands down. Miniram will cause you all sorts of fuss. There is a couple guys on here with blown singleplanes, and Orr has a turbo singleplane.

Lots of guys on other forums with twin turbos putting down over 800rwhp with less than 400 cubic inches.. Insane power. Most are running EFI singleplanes, or carb dual planes believe it or not.

-- Joe

Yeah, my car drives around very nicely even with the stupid loose converter and 2.73 gears. Its a 401 with 195cc AFR's but only 9 to 1 compression and a mild 233/233 cam. When boost comes on it gets pretty insane but distribution with air seems to be good so far without having checked anything yet. Driveability is fine and seems pretty responsive and the tune isnt even 100% yet. I like the single plane.

I'd prefer to get the single plane ported out and flow match the runners since I've seen a few tests and there is quite a large variance in flow between each runner, as much as 40cfm. Thats a major difference.

I have yet to check all my spark plugs and do plan to do so soon as I can. I'm curious to the distribution so far with my single plane. I havent noticed any problems so far but I havent monitored anything. I have the elbow with divider wall in the elbow so that all the air does not follow the back wall and favor the rear of the intake plenum. Does it help? I dont know for sure but it makes sense to me. Pressured air does not like to turn sharply so air will favor the outside wall of the elbow where the curve has a larger radius. But air will have to turn 90deg out in all directions onces it smashes into the plenum floor and gets redirected to the runners.

Miniram I have heard has distribution issues and I would think the rear cylinders would be force fed air more so than the fronts. Tune them rich and you can bet the fronts will be much more rich, but still a safe tune. There are some fast boosted LT1 intakes out there but they are sequential injection and can offset the injectors to compensate for flow differences.

I dont know what you are planning for EFI management but I use code $59 and its batch fire. If you use something else thats sequential and has injector offsets for front and rear cylinders, then miniram is ok to use.

Powerwise, i dont think you will loose anything either way. Miniram has short runners so low end torque is gonna be low anyway compared to a single plane.

Sorry to say it, but your thoughts are backwards and I mean no disrespect Orr. I had my Miniram for 8 years and the front four cylinders 1,2,3,4 ran clean all the time, but the back four cylinders where always rich. Every time I took off the intake 5,6,7,8 runners were coated with fuel residue and also the plugs confirmed that too. Cylinders 7,8 were the worst! You could go sequential, but the fact would still remain poor air distribution and that equals loss of power because all cylinders are not getting same amount of air. That was my reason for switching to a Pro Ram, now when I check my plugs they are all burning the same and the car pulls really good even with an old cam like the GM847. I can't complain, but I do wonder how it would respond to a custom grind from Joe Overton?

Sorry Orr if sound like I'm flaming on you, I would never do that to anyone on this board.

Hey guys, thanks for the responses. I switched to the 0411 (LS1 style) sequential setup. Not sure if it has any way to seperatly manage the injectors. I guess AFR is in leage with TPIS because they keep telling me to go with the miniram. The sells guy said the vette guys usually cant run a single plain because of low hood clearence so they mostly run the miniram. He said there are several guys who make big power with it and that sequential injection helps. I, so far, plan to run the miniram na and switch to a single plane with boast. Unless I find a good deal or something changes. Here are some pics of the elbow I plan to use. I know it won't clear the thermo housing. We might build a shorter one that will clear. This one is made for the ls1 stuff.

Here is another version. Too tall I beleave but still cool. He sells these for around 200 bucks too. Better price and simular product as intakeelbows.com

I take your point as no disrespect Its an open forum. Your not the first person to say this about the miniram. I have heard both ways on the Miniram. I have heard some say front run lean some say front run rich. But you are n/a correct? I hear the miniram acts differently under boost. My stealth ram on my n/a 383 did the same thing as your motor did. Rear cylinders were coated with fuel residue compared to the fronts.
Under boost I think the pressured air would tend to skip over the front cylinders more since denser air is harder to turn and more than likely the air velocity is higher too depending on your inlet pipe size.

I have also heard/read that once the plenum is fully charged to maximum boost, the cylinders will feed from that charged plenum and thus air distribution is somewhat eliminated as long as the plenum volume is great enough. Air will move from high pressure to low in the cylinder so each cylinder should get somewhat equal flow depending on how much each runner flows.

With sequential I do believe you can offset injector flow to compensate for rich lean variance across the cylinders. Most of the guys run singleplanes that I know of. The big hp guys that run front feed type intakes like miniram/HSR style have a custom sheet manifold thats tapered to the rear to limit the amount of air thrown to the rear cylinders.

Well I kinda figured you were talking about boosted application. I still have what I like to call "Turbo dreams". I'll start my turbo project one day when my money stop being funny and that will be never LOL.

I have read similar things to what Orr is talking about with the LT1, Mini-ram and Stealth-ram. The Rear cylinders run a tad bit rich NA and the Rear cyl run lean under FI ( or you tune a bit rich so the rears are right and the fronts are rich). This can be compensated for on Sequential injections, but with batch fire you get what you get.

Does anyone know if the ls1 computer like I have (0411) can seperately tune the injectors? I have found a complete 1204 miniram for 750. Does anyone know where i can get it ported to a 1206 gasket? I would try it myself but I'm afraid of getting it uneven. AFR said they would port match it for 275, That sounds fair but doesn't include any other porting. TPIS used to port intakes but don't offer this service anymore. I am still throwing the single plane idea around but I'm not sure. There is a guy on the vette forrums with a 454 sbc, afr 230 comp heads 252-260 s/r can and he said he LOST 3mph by switching to a single plane over his miniram. Granted his miniram flows 410cfm but still you would think at that level a properly setup single plane would out perform any horizontal draw intake. Food for thought.

Just my .02.....my single plane is far superior to my HSR in my setup but that's just my opinion and the HSR is not a miniram by any means.

Was his single plane ported out like the miniram was? Those heads flow darn near 360 cfm. Single planes usually just touch 300cfm. NO wonder he lost power if the single plane wasnt HEAVILY worked.

My buddy says LS1 ecm cant tune individual cylinders but it is a sequential system. I dont know if there are any offset values available to tune rear from front

You can't tune those injectors individually....I have HP Tuners for tuning my wife's car and 2007 Truck. However, you can manipulate the injector offset, pressure, etc in the tune.

Early 99+ vcms use a VE/MAF table....later E38 vcms, etc use only maf tables.

Support your country and dont buy chineze crap please

to start out im glad edelbrock finally updated their crap and put their true 185cc intake port volume. I measured and got 190 on mine actually.

Single Plabe EFI....F**king AWSOME.. simply put dude. I have the original pro flo set up..with the 1000cfm 4 bbl throttle body.42 lb/ph Venom injectors with an XM 278 cam. with my 2800 stall and 3.73s...every time i drive it fills like the first "fast" car again. its very low matainance. with 3.73s ...I still get about 20 miles a gallon when i keep my foot out of it.