I have to admit, I was wooed by the last month's Chevy HiPo rag and their use of the xfi280 in a motor similar to mine. I have long lusted over going to a single plane EFI intake and I figured that cam may be the one to do it. Then I started playing with an old copy of EA analyzer and it has started to make me question my combo... So I'll list my combo below and attach some dyno graphs and maybe you guys can sound off on what you think is going on and what normal numbers are for a 383/SR/219. (I know numbers aren't everything, the real source of my motivation is being edged out by a nose when going head to head with a buddies C6, gotta fix that!...I'm in an 86 Y-body.) Here are my dyno graphs: This was when I first got the motor setup: This is after an autocross and with the same plugs as original, I think they were past due...: The reason this all comes about it, is when running my combo in EA, I have to use non-ported heads to get near the same numbers, though it still peaks about 100-200rpm higher than the dynos show and when using my flow numbers for the heads (which this has made me doubt) I am running ~500-700rpm shy of where the power should be peaking. Any input would be really appreciated... Here is the motor. 383 non-forged, hyper pistons (10.3:1) Dart Pro1 200cc heads ported with this flow sheet (I hope I wasn't scammed here) LPE 1 5/8 Long tube headers into a y-pipe to 3" center to Magnaflow y-pipe out 1.6 full rockers LPE 219 cam, 219/219 .56/.56 lift with 1.6s SuperRam intake (The base looks like it had been gone through some (had some epoxy patching on one of the runners), but not extensively) 52mm Holley TB, gutted MAF

Your Dart Pro One heads flow almost exactly the same as mine. We are within a couple of cfm of each other.

Interesting that your motor peaks around the 5000rpm mark. You need to move the power band up higher for more power. As far as the numbers go a Mustang dyno will read lower.

I don't know what your exhaust system is like or your cold air intake from the filter to the throttle body. They could be holding you back some.

The cam is deffinetly holding you back from making power higher up in the rpm range. The XFI280 appears to be a good cam for our applications. Alex has one in his 400 motor with a Super Ram. Let me just say he killed you in power. Far and away more than just the difference in cubes and the Mustang Dyno.

Mine peaked around the same rpm. I had 383, 10.8:1, afr 190's, lpe219, 58mm tb, ported base and slp 1 3/4 shorties with 3500 stall and 3.73 gear.

Take it to the track and see how it runs. The dyno numbers don't mean anything and many people(including myself) have gotten their feelings hurt at the dyno. It's never as much as you think it should be.

My above combo in a 3700lb gta ran 12.90-13.00 at 110mph for 2 passes before I hurt the ring lands on 3 pistons running it lean. I started burning my own chips once I put the motor back together. The mid-range is where the super ram is best. I almost put my car into somebody's front yard one day at 45 mph when I floored it and the car started fishtailing. Who knows what the car would have done if the air fuel would have been correct.

If the base and runners aren't hogged out to the max you are leaving something on the table. I've changed many cams and intakes through the years (stock, sr, lt1, miniram) and I'd go back to the sr-lpe219 combo. I never should have sold that stuff.

The torque looks way low. What tranny/convertor do you have?

funny, because your heads flow more than mine.. difference being cam, carb and headers.. i was shifting at 6700 on 10.6:1..

seems to me that you should ditch the efi and economy cam.. something in the XFI lineup would probably be better.. like the XFI280 i hear is a powerful piece.. i would drop an rpm air gap topped with a 750DP.. 400 at the wheels.. but thats me..

hope you get this sorted out

I think it's all about what you want out of your car. Personally dyno numbers don't mean jack to me. I've been w/ 89gta383 to the dyno and watched his car put down what we considered low numbers. Take the car to the track and its better than you expect from the dyno numbers.

I appreciate the replies guys. I 100% agree with you that the dyno numbers mean crap. In regards to the numbers, I am more concerned about the RPM. The motor is peaking lower than I was expecting it to and I don't want to plan future mods if somethig is amiss.

1989GTATransAm, I agree, I thought it would peak higher. Airfilter could be collapsing as it is according style and then there is a big flat filter. I don't think it is a huge restriction. Where can I see Alex's dyno and engine combo. I'd love to see where he peaked power at.

89GTA383, I'm glad to hear its about on par RPM wise. That is reassuring. The transmissing is a 4+3...(Y-body), aka manual. Torque is low? What kind of numbers were you getting?

5678TA- Thanks, I want to go carb'd...intake at least. I like EFI too much even though it can be outrageously expensive at times. I hope I get it sorted out too.

Chris89GTA,- I totally agree, that is why I am more concerned about the RPM at peak power, than the actual number. I do know I want more performance though, regardless of numbers.

You have a PM

Also the AFR on the second run looks a little lean to me, I would try more cam and go from there.

Could the fact that the first one is with a wideband in the longtube collector and the second one is in the tailpipe explain the difference?

IMO, and using those cylinder heads, based on a 383 build my choice would have been a single plane or mr style intake. I would have chosen a camshaft with more duration @50 then the venerable 219.
Has the SR had any port work done (matched etc.)?

Both myself and a friend with a Corvette switched from a SuperRam to MiniRam. I do not have dyno numbers but my best ET with SR was 12.00. I changed intakes and improved ET by .25 seconds. My buddy with the Corvette went 11.6 with MR, 219 cam and some ported Edelbrocks.

Some people may have luck with a SR, I didn't. My opinion is you can stay with the cam but change intakes and you will pick up power!

www.geocities.com/dzperf

Your air/fuel ratio is pretty high! (near 14:1). You should try to go near 12,8:1. I'm sure you will get some HP. And don't forget that you have a stroker engine, i don't think you will reach high rpm.... But you should get more HP. I hope you will solve your problem shortly. Try some colder plugs, since you have High comp. pistons and you're stroked.....

mseven---- I think you are absolutely right. Sadly, this was my first motor build and hindsight is 20:20. I don't really want a motor that peaks max at 5500-6000 and so I went with the 219/SR. Now I feel a bit choked. After seeing the 406 with an xfi cam, if I can produce a similar curve (peak torque rpm wise it is about the same, so it might be just a bit higher, I think I'd be pretty happy.)
The SuperRam base had some port matching done, but I think I'd like to send it off and give it a good workthrough IF I keep it. Any recommendations?

HiTech5---- Awesome, I have considered the LT1 swap (I think slightly shorter runners than the MR) but I really had no clue how the 219 would act with it. Do you have any clue what RPM you peaked at? 12 flat and below, sure sounds like you were making good power!

Mekano---- I think the AFR is ok. If you look at the first graph (wideband O2 in the header collector) the AFR is ~12.6-8 the whole time. The second one was with a tailpipe 02 sensor at a less respectable shop. I've got accel shorty plugs right now, I'll have to pull them and check them and see what they look like. And you raise a good point, the 383 is pulling down the rpm band.

Does anybody produce converted single plane intakes? I'm just curious what the self-fabbed to pre-made price differences are.

Thanks again everybody for the replies. I think I'll keep lurking and looking at intakes/combos as more people use the xfi series and maybe I'll have one soon.

Your power numbers look OK to me but the RPM peak is low. I would port the superram runners and base to allow the engine to peak a little higher. The engine in my sig peaks at 5200 RPM with a ported superram.

Yeah, I think the intake is choking it bad considering it is a 383 too. Where did you get yours ported? Price? Pics? (Did they merge the plenum divider and siamese the runners?)

intake is slighly choking it, but not so much as the cam. I would agree with everyone here that your power curve should be higher up in the rpm range and should make alittle more power.

i can see 340-350 whp with that setup.

Whats the advertised duration of the LPE 219 cam? i always heard it acts bigger than what it is, and on your motor i'd expect near a 5500 rpm peak with those heads, but again that intake may be limiting you abit.

I've seen a 383 hotcam dyno make 370whp but at near 5600 rpms. That was with a 4bbl type fuel injected intake from holley. your car with the superam should beable to make 350whp with those heads at 5400-5500 i'd say

Also the torque seems a tad low

I might of missed it, but what tranny are you running?

To sum things up you need your intake opened up and a bigger cam designed in the 21st Century. The 219 cam is of an older design and has lazy ramps compared to todays cams.

Port the intake but keep the cam. The 219 cam works very well in a 383 with a ported intake. My corvette with the 219 cam ran 11.81 at 114 MPH with a ported superram.

The worst restriction on the superram is in the base. The untouched runners flow 289.18 cfm. The untouched base flow about 240 cfm. I would concentrate on that. The area on top just behind the injectors is the worst. A user on this board was able to almost get 300 cfm out of the base just by removing this material, welding in more material, reworking the injector bungs and raising the fuel rail. Lots of work but any attention to this area can only be good.

"A user on this board was able to almost get 300 cfm out of the base"

Actually it was more than 300cfm and done by a couple of users.

Shaggy56 is correct in regarding the base.

So is there a link for a DIY to replicate this? Does someone on here do this as well. I'd love to get 300cfm out of the whole thing, but it sounds like the base needs it first!

I know there was a post by Kevin91Z. Maybe one by JerryWho the man behind the scenes.

basically its just porting the TPI base and raising the roof. you cant go too high without running out of material so you need some material welded to the top of the base runners by the injector bosses. Then you need to raise the injector bosses alittle to compensate which may need to raise the fuel rail. Lots of work i think to get 300cfm

You should only look to fully port or extrude hone that base. If it flows 240 stock, you probly could get it towards 275cfm without too much problem. That will really help that cam breathe with those heads. stilll a slight restriction as you generally want your intake to flow abit more than the heads can flow

When you say "SuperRam intake," are you talking about the Accel intake or the Edelbrock or the TPIS?

I've had both a TPIS and an Accel and the Accel was way bigger (both 100% stock)

(Accel = block off plate, TPIS = no plate in pics)

I wouldnt worry about what intake is "bigger". The inherent problem with all the intakes is the roof just behind the injectors which need material removed and possibly more welded in and the injectors and fuel rail raised. If you take measurements of your intake like I have you will see where the restrictions are. I have some formulas to find cfm from cross section area.

Here is the original thread.

http://www.thirdgen.org/techboard/tp...anifold-2.html (Visual TPI intake manifold ports)

The original Accel intake also has a better entry into the heads. Out side of the First I think it is the best TPI intake manifold available. It appears that the later Accel TPI intake manifold is made by Edelbrock. The runners look the same.

i'd aggree.. if you want TPI go with first or be prepared to heavily moddify your aftermarket base/runners. First seems like a great TPI setup with good flow numbers, the TPI that GM should have made. BUT i havent seen dyno numbers yet from anyone/anywhere so take that into consideration

The only thing I dont like with the First unit is the runner length that your still dealing with. The lack of performance tpi intakes are very frusterating. I paid about $350 for the newer version Edelbrock manifold so I have less problems with hacking it up. Im in the process of fully porting mine since I dont have heads that flow much more than 250-260 cfm and plan to go with a supercharger anyhow. If I end up with some higher flowing heads I will either weld in material or just go to the Miniram.

Wow, awesome info guys. This is awesome. If I could get 300cfm out of the SuperRam there is no way I'd change intakes. Especially since I only have a 1205 intake on the heads as well. I however do not trust myself with a welder that much...

I almost forgot about the BBK intake as well, that thread reminded me, that will be interesting.

1989GTATransAm, do you currently have the car together and running or are you still working on the intake or? It seems you have about very similar heads to me? Are they mildly worked as well or is that out of the box?

Very cool info guys!

The car is back together and running with the new cam and valvesprings. At the moment it is back in the garage for an oil change and recharging the air conditioning system. Next step is some more dyno pulls.

My heads are the Dart Pro One 200cc heads and yes they have been worked over not out of the box. The new Dart Platinum heads are supposed to be better. The new AFR 195cc Eliminator heads flow like mine new out of the box. Maybe even better in some areas. I would say they are the hot ticket for now.

I don't see why you could not get 300cfm out of the Super Ram setup. We have one intake manifold that flowed around 305cfm with only a 2.2 cross sectional area at the head entry point. That is a smaller than a 1205 gasket. Some welding would be involved to raise the port height around the fuel injector bungs.

Curious when you welded it were you able to eliminate having to mill the intake to head surface? Or did you still have to weld at the entry point and have the intake milled? Im assuming the welding may cause some warping causing you to have to get it milled anyhow. Im just concerned about fitment issues after milling the intake. Would be awesome if someone started a service for this mod.

That is just plain awesome.

The welding involved is around the injector bungs. The link you posted above has a good picture in it of where the welding needs to be done. Look at the picture on post 55 of the link.

No welding on the mating surfaces whatsoever. Disregard the raised injector ring on one of the injector bungs. Jerry was doing a little experimenting for something more drastic. Not needed for what we are doing. Just look at the welding portion.

Thanks for the quick response and more detailed explanation of how to gain 300 cfm. Really doesnt sound all that difficult if you have a compitent welder weld in the extra material.

SRs tend to peak at 5200 rpm in 350s.

With a 3.48" stroke, 5200 rpm results in a piston speed of 25.1 ft/sec.

A 383 with 3.75" stroke achieves the same 25.1 ft/sec piston speed at only 4819 rpm.

Based on this, I would expect to see a 4800 rpm peak with a SR in a 383, which is consistent with your results.

I'd say your engine is performing as expected.

What did Tom Wong have to say about your dyno results?

Will this expose the injector tips out into the port itself? If im not mistaken stock there recessed. Removing material from around them looks like it would. With out raising the injector itself. Any problems having it further in the flow of air.

Great work guys thanks for sharing!

With the one I did the injector did not protude into the port. The Edelbrock manifold port can be widened some to increase the csa. What you want to do is create an arch in the roof of the port for a better entry angle into the head and also help in the increase of the cross sectional area.

If done properly you wont have the injector protruding into the air flow. If an untouched intake manifold you might be able to get some arch in the floor of the port to match the head port floor. That will also help in the entry angle from the intake manifold to the head. The early Accel TPI intake manifold already has this feature and that makes it a better manifold to start with.

Hi Allen..I think understand,most of this work is just behind the injector further in the port? No so much at the injector hole itself.

IM lucky i got one of the original Accel SuperRam bases. Although i did pay a premium for it. I ported my runners out as far as they would go and leave enough material for strength. I did a half hearted attempt at the base. IM going to pull mine off and give it a full going over.


Good luck with your new setup im looking forward to hearing how it does.

Bah, jus extrude hone it like i did for the base. Fully port the heads
Oh, and get a 280xfi cam.
Thats all....
Ur torque curve looks nice.

1989GTATransAm, definitely keep us updated on your motor progress! And if you want to "practice" on any other SRs let me know.

Tequilaboy- That makes sense to me as well. Good to hear. Tom didn t say too much. I had swapped out from a 213 flat tappet before this and I was making a little less torque but it seemed like it was what he expected from it. Corvette0096 was there and we compared to his TEA ported SR and needless to say I called TEA, but they no longer port SRs...

Cali92RS, where are you peaking at? Are you running the 280?


This thread is awesome. Thanks everybody!

Like every one else has said there is power to be had by fully porting out your base. Something on my list as well.

So you swapped out a 213 cam for the 219? Was this the LPE 213 numbers like 224/234 duration. I have this 213 in my 406 and would be very interested in hearing any before and after results/thoughts if its the same cam. If you have any dyno sheets with the 213 i would love to see them.

I'll have to go through the external harddrive and try to find it, but I can tell you that the new LPE 219 on his dyno made 338rwhp/396rwtq and the flat-tappet LPE 213 made 318rwhp/420rwtq.

So I gained 20hp and the motor rev'd a lot easier but I also lost 24rwtq. I wasn't totally pumped about these results...

How much did the extrude hone cost ya?

Thats interesting reduced friction probably gave you the extra power. Surprising to see a torque loss though. Those are the two cams LPE designed for the 383/406 engines in conjuction with the SuperRam.

How did the two cams act? As far as idle part throttle kinda things?

I didn't change the idle for either and they were both fine at part-throttle. The only difference was really in how fast it rev'd with the 219, which seemed faster. Does that answer your question?

I mean honestly, thats why I was bummed, I was hoping for more of a change but it was an expensive...nothing.

One other thing you might want to look at is a WOT data log. Check your MAP values, if they are not at least 95% then you have an air intake restriction before it ever even gets to the SR that needs to be addressed. Could be part of the power you think you're missing.

But I also have to be honest with you - my 383 MR combo doesn't feel like what it's supposed to be putting out either....

The short runners will make things a little soft below 5500rpm compared to say a Super Ram or modified TPI. However above that they should start to come alive. Again you need the proper matching parts. You also need as much compression as your local gasoline and engine combo will stand.

Yep, I'm resurrecting this thread from the dead.

For MikeH and to also ask:

1989GTATransAm, how are those modified SR's coming? I really would like to seem some results...


LPE 213 dyno sheet

Going to pick them up from the welder tomorrow. Then the machine work begins. Refer to the JerryWho thread for details on how to open up the intake manifold.