As the subject states...only reason to own one would be it's nostalgic look for an old rat rod. Yes, I'm not in it to enter horsepower race. My question for you tinkerers...should I buy it or should it be a hard pass? Doesn't come with a harness, I'll probably use a modified TBI harness with a '7747 ECM. All comments good or bad is welcome $.02.

 

I’d say if tb are tight and it’s 200 or less why not

 

Once the CFI is sorted out, and they usually need some sorting, they are pretty bullet proof. Big impact with onlookers at cruise nights.

 

It kinda reminds me of smokey yunick sy1

 

It's listed as unknown condition unknown mileage $100. I probably should do a search but if ya'll can just educate me here that would be great. I'd like to hear some specifics about what the 305s came with as well as a 350. TB bore size same between the different size engines but what about the PPH injectors? I think that should be about all I want to know since I'm not chasing hp.

 

I'm almost positive both 305 and 350 had the same 275 CFM injectors as the Iron Duke but 2 of them. The LU5 and L83 had the same cam IIRC. Same specs as the previous LM-1 350.

The biggest things to chase on a CFI are vacuum leaks, especially at the top plate of the intake where it bolts to the base.

When I bought my '83 it really ran like crap. It was unbelievably slow and unresponsive and felt like 90 horsepower. Tons of vacuum leaks and other stuff. It ran pretty good once it was sorted out. Later I added L69 2.25" exhaust manifolds, had a 3" exhaust made, when you could still have one made and got an SLP 2OTL muffler/tailpipes. It picked up a few horses and sounded great.

 

Nope. The SY1 was a single-carb intake.

You're thinking of the dual-carb GM intake system from the old Z/28. Supposedly, the SY1 was the under-the-table, prototype replacement for the dual-carb manifold; but GM never actually authorized it for production. Became an aftermarket product.

Why would you NOT be able to have a 3" exhaust system made?



I looked at a GM Crossfire Injection manifold years ago. The runners are so tiny as to be a bad joke. Might as well start with a better manifold instead of grinding the livin' crap out of a Crossfire piece.

 

Not too many convincing arguments...I couldn't leave those 1/2 blocked ports alone but at the same time I'm that lazy that I'd pass on it. I have a allegedly better '87 LG4 here that can accept a roller cam/spider but that means modifying the center intake manifold holes not being a huge ordeal. At this point in the venture, I'd grab it for the complete intake and it'll sit on a shelf next to the other manifolds I have here at the stable.

 

Because all of the old time exhaust shops that would bend you a custom exhaust either no longer exist or just don't do it anymore.

Trivia: The Crossfire intake was based on the old Z/28 Cross Ram intake, re-used to avoid paying for new tooling. Obviously that intake was sized to take 2 Holley 600CFM carbs and rev to over 7,000 RPM. The runners were drastically reduced in size to create high velocity at low RPM and work with the two 275 CFM TB. Everything was all in by 4500 RPM. It was a very compromised system. GM powertrain engineers were working to improve it, but by that time engineering resources were shifted towards development of the TPI and all work on the CFI stopped. One engineer stated that if they could have reversed the orientation of the intake, ie., the location of the 2 TBs, they could have had a much better performing intake.

 

Didn't realize that was an issue. There's still custom-bending shops around here. It's how they improve their profits--they buy cheap, straight tubing and bend it to fit whatever the application calls for.

I don't believe this. The Crossfire intake has so many changes from the older Cross Ram that none of the tooling would be re-used.
Crossfire has EGR, Cross Ram does not.

Shape of the top plate, and the gasket surface of the lower part is completely different

Runner cores totally different.

 

That came directly from one of the engineers tasked with the development of CFI. He was interviewed in one of the books on the history of the smallblock Chevy. If I have time this week I'll try to find it and post a screenshot. Lots of interesting stuff.

 

Yeeeaaahhh.....it may have come from an engineer -to an author, through an editor an in a book. But that doesn't make it right or accurate. I'm with Schurkey...there is no WAY that the CFI intake shared any dimensions with the Z/28 Cross Ram intake other than port location, flange width, and distributor hole.

Roy Midgley stated (and I can post a page shot) that the LT5 HAD to have the same bore centers as the SBC so that it could run down the same assy line. Buuuuutttt....they already knew that the LT5 wasn't ever going to be on a GM assy line, so....


There is TONS of misinformation in auto mag/book print. I think it's safe to say that the CFI was inspired by the Z/28 Cross Ram...but used the same tooling? No way.

 

Here you go guys. Take it up with Louis Cuttitta who was pretty well known back in the day.

 

Why not get a roller cam, 1 piece rear main seal 305/350 and use a non computer controlled Rochester or the CFI on that??

 

@chazman Could you pass along the name of the book? Looks to be an interesting read for the winter evenings.

I still have my CFI stuff packed up, harness, ECU, Air cleaner, hood parts, intake, and all the specific parts. I would love to find someone who would take the three tubs of stuff out of my storage building (for free even). I can't bear the thought of tossing out this stuff since someone might want or need the parts for their own restoration. But I admit those chances are slim since CFI always got a bad rep (the well-known phrase Cease Fire Injection).
I would have gladly kept my car with the CFI, but the POS already started converting to carburetor when I rescued it.

 

Will do, when I get home. It's a really interesting book.

Please find a good home for that stuff, I know CFI has it's drawbacks, but it's an interesting system.

 

You've proven that it's in print. The manifolds are so different that there's no way they used the same tooling.

 

So what would be the reason to use a Crossram design like that, when even the engineering team tasked with developing it, didn't want to use it?

 

Old man cross ram nostalgia and GM already had the TBI units in the parts bin. If the 2-barrel TBI had of been out, then the Vette would have had it instead.

 

Well, I'm not cheesy 80's car-book author....but, "YES PLEASE!" I'll bite.

1. "We developed it so there was more hot air air to the air cleaner, called "Thermac", and sort of saved it."
1.2: Thermac was introduced by GM in 1968 and the system on the CFI car was not meaningfully different than the one on the LG4...at the same time. Not even the "more hot air to the air cleaner" part.

2. "We never liked TBI because the throttle bodies were the wrong way. The throttle shafts were parallel to the to the crank shaft and should have been the other way. If they had been the other way, we could have gained distribution and many other things, but it was too late to change."
2.2: I mean...give me a f'n BREAK people. You could change the orientation of the TB's in your garage, in....IDK....a DAY?? And 2.3: WTF has TBI got to do with ability to position throttle shafts?? NOTHING. But, 2.4: way, WAY more importantly than that is this fact: The TB shafts were not parallel to the crankshaft!! They were/are perpendicular to the crank!! LOL!!!!

Should I keep slaughtering that "engineer's" supposed quotes?...

 

If you want to keep "slaughtering", go right ahead. I never met Cuttitta, but he doesn't strike me as a dummy. In addition to developing CFI, he and his team helped develop TPI and he had a big hand in the development of the L69. In fact there's an interview with him circa 1983 describing the changes made to create the L69. I also believe he was at GM for decades before that, working on carburetors and the original FI on the Corvette. There was another passage I seem to remember where he said if the TB positions were reversed, ie., the driver's side was forward and the passenger side was rearward, CFI would have had much better distribution and performed better, but they weren't allowed to change the orientation of the intake..

Anyhoozit, just wondering why you think GM would use a Crossram manifold like they did, if it wasn't to re-use some old tooling?

More trivia to get everyone's panties bunched: Before CFI, GM tried to create a version of Tripower with the engineer who worked on Pontiac's Tripower. The idea would be the same as a GTO. Putt-putt along with great economy on the center TB and and open up all 3 TB s when you put your foot in it. Apparently that was quickly found to be unworkable and development started on the CFI right after that.

 

Here you go.

 

No doubt about that.

 

Chazman....It's interesting that you totally glossed over the two obvious and easily verifiable facts that I shared with you. Didn't even acknowledge that this "engineer" couldn't accurately ascertain the direction that the throttle shafts were situated. I mean....that is a verifiable falsehood. Open the hood of a CFI car, and look at the throttle linkage/shaft!! LOL.

O.K. Here goes. And keep in mind here....I had a CFI car, ran the wee out of it for over a decade, so the following is first hand, real life, actual experience.
3. "......the throttle bodies were icing...."
3.1: I removed MY "hi-flo" THERMAC entirely and plugged the entrance. I also plugged the main air entrance to the air cleaner housing. I then, wired my cowl valve wide open all, all the time. Finally, I copped out the coolant passage under the runners, welded it off (so, no hot water under the runners). Never had TB icing. Not in Mass, not in Maine, not in UT, not in winter, not in 10 below zero...never. Maybe they had that problem in testing in Antarctica? Maybe at the North Pole?
4. "...these two throttle bodies were mounted essentially out over the valve covers..."
4.1: Verifiably false, look at a CFI engine. The TB's were directly over the intake...AND the thing used hot air intake....no different than any typical carb intakes of the era. Here...let's use our own eyeballs, and have a look, shall we? IDK....*I* see the valve covers, and they're not "under the TB's"....



5. "...and there was no way to get any exhaust heat up there as there was with a carburetor."
5.1: Weird. Same "engineer" was already quoted, talking about their "hi-flo" THERMAC, that had "....sort of saved it."....right? Explain to us how the air path and THERMAC would function any differently with any TBI system....vs a carb?
6. "...we sent a bunch of guys off to school to learn how this thing works...."
6.2: I mean COME ON. The engineers sent a 'bunch of guys off to skool to...." Geezus, man. They were the engineers!! Where'd they "sent a bunch of guys" in ~1981, to skool the powertrain engineers on fuel distribution and chip tooning??? THEY, the engineers had to figure that out, back then! There was no "CFI intake tooning skool" in 1980/81!
7. Last but far from least is this gem, as it relates to your claim that the CFI was made from the Z/28 tooling: "In appearance and CONCEPT, the HARKENED BACK to the days in the late 60's when the 2x4 bbl induction system was used on the Z-28, but it by no means developed that kind of power."
7.1: There it is. "in appearance and concept". IOW....not the same thing or made by the same tooling. That sentence right there, sinks your argument, and if that doesn't....please proceed to the end of this post....


Well? If he said the things that are "quoted" in the print above, he's a dummy. You don't have to be too smart to figure out throttle shaft orientation relative to crank center line....yet this engineer got that wrong. (?) I doubt that he said those things though....I'd BET that the author/editor took a few liberties when producing that book.

Yeeeahhhh.....that don't sound too bright either. If you switched to orientation of the TB's....they wouldn't ah...you know, even sit on top of the intake's top plate. But, let's pretend that they would. THINK....if the TB locations were "reversed" such that the driver's side were forward and the passenger side was rearward", first, GM would have done THAT...b/c that would be a real easy change to make. As mentioned above -a guy could do that in a day, in his garage. But more importantly, the driver's side TB would then be positioned directly above the runner mouths for cyl's 2&4....and the passenger's TB would be directly above the runner mouths for cyl's 5&7. Explain to us, how that is in ANY way, better than positioning the TB centered between the runner mouths of 2/4 & 6/8....and 1/3 & 5/7? . And before you try to explain that....note that the '69 Cross ram pictured above positioned the two carb's TB's in essentially the same place relative to the runners' mouths, as the CFI intake did. Huh. Weird.

Easy. Same reason that GM used any intake system of the era, or any era: It met the criteria.

Really. "Before CFI" as in, during the 60's? B/C Chevy did put "tri power" on some of it's engines in the 60's.



Now to put this ridiculous assertion that the two intakes -made 15 years apart, used the "same tooling"....let us grace our eyeballs upon both specimens to see if we can figure out how that could have possibly worked....
1969....


1982....



^Note the orientation of the throttle shafts!^

.....given their completely different shapes, sizes, T-stat location, EGR. system, top plate, port size, runner shapes/paths....everything! Explain that, to us please.

 

What criteria? This was the ONLY question I asked you. The criteria seemed to be, use this intake and figure out how to work it with two Iron Duke TBs. Why try pushing water uphill with an intake that is not well suited for an appropriate outcome? Stupidity? Penny pinching? Seems there'd be better ways to get 2 Iron Duke TBs to do the job.

No, you misunderstood me. This would have probably been circa 1980 when GM was trying to create a FI system for the 3rd gen using those TB. The "tripower" as in 3 throttle bodies, was quickly abandoned and work moved on to CFI.

 

Also, while we're at it, why not simply use the1982 Cadillac 4.1L TBI system which used a single TB with two injectors giving enough CFM for a small V8. Seems simpler than going to a dual TB on a crossram intake to me. Somehow GM REALLY wanted to use that intake.

 

I DID answer you. You originally asked,

I said, quite clearly,

I assumed that being the well versed 3rd gen'r that you are, you'd have as good an idea as I would, what the criteria was at that time. NOW, you're asking a different question: "What criteria?"
The criteria that all engineers of all cars, need to meet? "What do people want from the car?" "What regulations must we meet?" My educated guesses are probably as good as yours., but in 1982?
*CAFE
*Emissions
*Raise HP/Tq over existing carb options
*Improved drivability/cold starting, etc.
*Reliability
*Packaging (low hood line)
*Improve "panache" ("EFI")
*Cool factor; "Crossram" "like 1969" etc.
*Cost. Used existing/off the shelf parts: TB's Injectors, FPR, fuel pump, sensors, ECM
It turned out to be a bad decision. I liked mine and it ran good, but obviously history hasn't been favorable to the concept that was put into production. Therefore, I agree with your comment that "Seems there'd be better ways to get two Iron Duke TB's to do the job". Agreed. I'd guess that someone pitched the concept, Initially it was liked for cool factor, power potential and packaging....getting the concept to actually work in the post emissions/CAFE world likely proved to be way more difficult than anticipated and they were out of time and had to make it work.


*Packaging (low hood line)
*Cool factor; "Crossram" "like 1969" etc.
*Cost. Used existing/off the shelf parts: TB's Injectors, FPR, fuel pump, sensors, ECM


How cool is the induction system on an L03? That's possibly why.

 

Dude, they're exactly the same! Same tooling, I'm sure they make the same power, flow the same cfm!!! haha!


these engines were before my time. But as a kid in the late 90s w these cars we all knew the cfi was really lame. It was a system riding the coattails of a cool design from the 60s. I had a few friends w cfi setups and the all ran like crap this was both in f body's and vettes. It clearly has potential w someone who can mod/tune it. But that was not the case for 99% or them.

 

I actually agree with all of that. I'm sure someone had the idea of a "cool factor" with a Crossram, configured in the same way as the early Z/28 motors. Perhaps there was also talk of re-using tooling.

It did have a visual "wow factor" for sure. FAR more than the later L03/L05. But GM moved on from it almost immediately, using lessons learned on TPI.

Like yours', mine ran great eventually. Every now and then I think about getting another one, but I've probably moved on from it. I certainly wouldn't be afraid of one, though.

Oh, regarding the Cadillac system, out of curiosity I did some snooping on it after posting last night. All the reasons you mentioned may have been valid reasons it wasn't used. But it was also flow limited. The TB on the Cadillac 4.1 barely flowed over 400 CFM vs the LU5/L83, 2 x 275 CFM.

Anyway, interesting discussion.

 

My vaca time officially started today and I was gonna make first contact...as fate would have it, the CL posting expired. That doesn't mean it was sold but I will check for it from time to time or un-CFI my mind!!!

 

Check FBMP?

 

I tried there, too. Once upon a time pre-covid...cruise in style swap meet, a guy had the complete CFI intake in the bed of his LC2 swapped S10. He remarked "I'm selling it for a friend." I replied "Can I get his contact info?" First contact we agreed on $30 for the complete intake assy. Second, third, fourth attempts to contact, dud ghosts me. Honestly I don't need the distractions and need to work on other long list of projects!!!

 

Both those intakes were cast by Winters foundry I swapped modified CFI to my car in 1993 and still running it.

 

WRT to the original question- working well a crossfire setup could be a lot of fun. You'll be figthing a great big uphill battle trying to make 500hp with it or run 11's, but I would argue that no mild small block intake assembly is more fun from a stop light. People talk about the torque that the TPI makes, it really makes a good midrange 3500rpm +/- a little. The crossfire instead makes massive torque right off the line, it makes the tpi feel like it, well it does, the TPI doesn't catch up to it till about 3500 or so rpm, and then the TPI is dead by 4500rpm and the crossfire happily revs to, well whatever the engine is built for (I'm not saying it makes power up there on a big engine).

They also get better MPG then any other setup, and run well on high compression engines (the stock LU5 crossfire 305 had 9.8:1 compression according to the '83 shop manual).

My 83 was my first car, wow, back in the 90's, and ultimately I had it running solid low 13s, with a stock converter, stock 3.23 gears (I blew them up at one point and swapped in the 3.42's from my '97 WS6, and it both went slower at the track and got worse MPG) and could consistently get 35-37mpg on the highway (it was hyper optimized for that, back then I was taking it on a lot of road trips, DC to RI and DC to FL, long story)

Oh, and yea, they work fine with the more typical TBI ecms (7747... ), better than the stock ECM.

I haven't had the car for probably 20years now, but I saved the crossfire setup since I've always thought it would be a cool swap into an LO5 truck. Of course, my K1500 2 door blazer has been gone since 2007... LOL