ok a lil background. i was working for a chevy dealer in the 80's and early 90's..good news was i got to go to all the GM school in Burbank on there dime. leave kids with her mom and dad and made a mini vaca with the lil woman..... i was the heavy line guy and got all the 2.8 rear main seal recall's. ... but i fell in love with the TBI crossfire F bodys and vette's. looked cool and i got to know them well. ... sense that time i have put them on a few TBI cars. easy swap. the last one i did was on a V8 swapped 91 S10. what im doing now is putting a 82 vette 350 in my dads TBI truck. I have never done a aftermarket cam swap on a TBI before that worked well. it was like i was trading something for something ...have good street .runability or mid-top end but never could get both and a happy map sensor so i stopped swapping cams altogether. i got a good idea what i want but was wondering what bump stick ya would use in you 84 vette with a TH 400 4.56 gears crossfire injection and weighted in at just over 5300 pounds. not looking for a hotrod here .. just a stick that will wake it up ... thanks.PS ... the intake itself has had a bit of port matching for better heads. i tryed to use a vortec heads ... not worth the work .i am using a set of heads from a 77 truck with a 64 cc chamber this time

 

I ran a comp 12-388-4 for a while. It pulled a little more up top and down low but was a close enough profile to stock it still ran great ok the factory ecm. It's a 206/212 instead of a 202/206. Very mild difference but for sure felt good. I wouldn't be going to wild in a truck imo so anything around or below like 218/222 is probably going to be fine but the bigger it gets I'm sure you know the less happy it'll be.

 

ya .. i was thinking 208/215 at the most with a 112 lobe separation 4.85-ish on the lift with 1.6 rockers giving the limits on the size of the TB's. i seem to remember reading someplace thay someone had used (2) 4.3 TB on one .... i have 4 intakes .. mite be worth a shot..

 

reach out to Tom at DCS... or whatever it's called called now. @Buccaneer is his handle here. He knows a lot of the intricacies with the system and may be able to point you to guys who have done stranger swaps.

 

Paul, your killin' me...DCS? Anyway, you can't stray too far on the duration from stock if you plan on using a stock CFI ECM or it WILL have issues. The lift isn't a big deal and the closer you get to 114, the better, but 112 is ok. You could use (2) two barrel TBs, but you would need a big inch motor to support that IMO. A 406+ would be a good candidate. I have thought about building a 421 CF with twin two barrels for a long time now. If you want to go bigger, than an EBL Flash II ECM is in your future and start laptop tuning, but then you can add all kinds of goodies to the motor. With a 5300lb truck, I would go with either 3.73 or 4.11 gear but maybe go with a 700r4 as well so you would have the cruiseability also at highway speeds and lower rpm. GL with your project.

 

The choke point for the Crossfire was the intake manifold. There were a couple of aftermarket manifolds for that engine, one called the "Renegade" may still be available, or there may be NOS available. Be aware that the later examples of that manifold had serious quality control issues and may require machining or even immediate warranty replacement if the thing was manufactured badly enough. I'm not sure if the issues have been resolved. I think I heard a few years back that the original producer was trying to get the tooling and manufacturing rights back because the folks that bought the design were building them so poorly.

With the stock manifold, very few mods for more power give you what you would normally expect. The stock manifold with the undersized runners just won't flow right into the larger ports on the head. Machining the ends of the runners to match the ports helps some, but you need the whole runner, all the way to the top to be enlarged. There's not enough metal up there to fix it. Headers don't help that, cams don't help that, and nothing else does either. You put a cam in that on a carbureted older SBC or an L98 would deliver additional 50hp, and you get like 5hp to 10hp gain on a crossfire with a stock intake manifold. Upgrade the intake after that, and you find the other 40-45hp come back with the upgraded intake.

 

listen... its been a long weekend. X-fire performance... better?

 

LOL Just bustin' on ya Paul. But, you are correct. Hope the rest of your weekend goes well.

Not sure where or who started that nonsense about us (DCS) selling any "rights" to our manifold, but that IS NOT or WAS NOT true. We NEVER sold anything to anyone. I still have all the original tooling in my possession and it is completely refurbished by the original pattern maker here in Phoenix. I just can't find a foundry to pour the tooling at a reasonable price and still machine it. If I could, they would be going out the door like hotcakes. I have a very long list of people that want one.

If you install an EBL and tune it properly, it will do just fine and run well vs putting a carb on it IMO. The key is putting the right combo of parts together and then tune it appropriately.

 

like i said .. its dads truck and it has 4.56's in it now .... i do have a 700 on the shelf that mite go on later ... but for now its what i have to work with. .. the s10 i did the swap on had a 700 and 410 gears... ya it was fun

 

the one intake i have i spent alot of time porting but i did go to thin on the first one i tryed to do. .... as for a cam. i am looking for a bit more bottom pulling sense its 4X4. .... useing my 461 hump heads would be a waist and the late 70's heads is what i used on the S10 with the worked over intake and stock-ish cam but just stopped making anything useable around 5000... but man would it come out of the hole ...

 

i almost got a renegade in 08 when i did the swap a impala....

 

That is the only problem... a real stump puller of a cam will stop making power around there. There are 4x4 grinds out there as well as marine ones... 12-239-3 would be about as wild as i would go spec wise and still have it work alright with stock parts... 12-235-2 is probably a better pick though... again, I can spitball all I want but even pretty heavily ported I think my stock intake will nose over around or before 5k... you'd probably have to cut back the runners some to get more out of it.

If you are going roller vs flat tappet then yes, you can extend the upper without hurting lower quite a bit with a roller imo.

 

i don't think pops has ever spun a mill to 5k in his life.. so running out of engine at 5k will not be a problom.. lol. as for me it bugged me to no end i even tryed useing a radio volume control to fool the map so it would run and idle with a 292 stick in it but still 5k it was all done. . like i said in my first post... i do like them and thay do work within there limits and i kinda got them figuerd out. but its been sense 2008 that i did a swap and things change. and i was hoping someone had found that sweet spot that made it a giant killer unit.... thanks for all yalls input but it looks like the old ways are the best ways..... il post some pics as i go along. should start on it laterr in the week..

 

yeah it's just too much working against you. Mine will spin to 6500 but I doubt it's making any more steam much past 4000... it was built with a renegade in mind. Good luck with the build. Look forward to seeing the progress.