Should I LS Swap my Crossfire C4 or Rebuild the Engine
 

I have only owned this car for a year now but have nothing but engine problems. After repairing tons of problems, it seems like whomever worked on her was a really bad mechanic. An example would be my latest problem was intake leaks. When I pulled the intake I found oil in the manifold because whomever pulled it previously did not use thread sealant on the bolts, In addition they installed restriction plates in every coolant passage. Well Yesterday it spun a main bearing. My knee jerk reaction was to rebuild the engine. Being on sort of a budget I started looking at what I already have. Well ironically I have for my boat engine that I never rebuilt , New Wisco forged Pistons , 5.7 rods, a 3.75 eagle stroker crank, bearings, gaskets etc. All I needed was a new cam and a good set of heads. So I impulse ordered a comp cams 280/.480 cam and a set of Blueprint engines 64cc aluminum heads to complete the engine. Now I am arguing with myself, with the build I am doing I don't think (almost positive) I can use the stock computer. This means there goes the crossfire injection, that I happen to really like. On the other side of the coin , I also have sitting a 5.3 vortec from a 2005 Tahoe with a stand alone harness from my YJ jeep that recently got totaled when someone decided to change lanes into oncoming traffic:mad: (told you I had bad luck) and an LQ9 6.0 that I could drop in. My dilemma is do I try to keep her almost stock or just swap it out? I am not really looking for stupid HP or to race , just want her to be reliable.

LS swap will take some effort and if you aren't planning on huge power... it's a cost of aggravation thing. Is the car worth it to you or is it better to just get out now and get something else?

If not looking for crazy HP I would build a 383 with what you have, I am sure you can make something work with your ecm, someone should chime in with experience with the cross fire.

Funny you said that, I was just thinking if i should just go pick up another C4 and call it a day. I can buy another one for like 2-3k Wich almost makes them disposable. The thing is I like the car and have rebuilt so much already right down to the instrument cluster.

The ECM is my biggest worry. I have HP Tuners and I program OBD II all the time . I actually just got finished modifying an LS harness to help a buddy of mine on a swap into his rock crawler. I drive around with my wide band O2 data logging to tune etc. but have nothing for OBD I. The 383 build should produce somewhere around 450hp its a 10:1 engine good vortec style heads and a healthy cam. I would love to build it old school and keep the crossfire.

I am not sure how tunable the crossfire ecm is, I do my own tuning on my 90, you may also be able to go with http://www.dynamicefi.com/EBL_Flash.php which would upgrade your ecm. Belowe are some videos I did on obd1 in my 90.

Thanks for the info. I will do some research tomorrow. I am pulling the engine tomorrow and stripping it down to access the damage. I hope spinning a main didn't mess the block up to much. I do have another 350 4 bolt main I can use but that one has a drivers side dipstick and that would mean I would have to search for oil pans.

If you want some motivation one way or another... check out here.

i just read some of your thread Funny 1st thing I noticed is that some of the people on your thread are the same as on my original thread. Buccaneer, Greg and hotrod roy are great guys and full of knowledge and help. Here is my saga

https://www.corvetteforum.com/forums...post1601255237

what's funny is I found that thread a little ways into it... i stepped back because it seemed anything I could think of had already been tried. Tom, Greg and Roy are great guys. They combined know more than I could ever learn in 4 lifetimes about these lol. I do know enough to be dangerous though.

Bill, only you can decide how much effort you want to put into your '84. But I would say you can rebuild the crossfire as stroker and replace the ECM much faster than swapping in an LS whatever motor along with a whole new ignition control that has to work with your dash instruments also. And it sounds like you have plenty of fun working the crossfire system.

But on the other hand if you want a real badazz '84 that LQ9 will do it and for not to much money - mostly the PCM/controller swap will be the headache.

Good luck.

if rods are OK just put a crank kit in it and drive it will out last car and dont cost much

Rebuild your original engine and forget the LS swap ideas.

Keep your Corvette original and get it to run like it did when new and then you should be happy.

I would rebuild the original block and be sure the machine shop knows what they are doing. I think the crossfire system is very creative and a neat feature when working properly.

My C3 had a 427 that was tired so I rebuilt it into my "dream engine", today the 427 has 12.25-1 compression ratio and runs very nicely. The only painful part was that the Big Block parts are far more expensive.

I thank everyone for their input. Yesterday I started pulling the engine. I have decided to rebuild the existing and do everything to keep the crossfire injection with the parts I have sitting around that I had bought years ago for my 383 stroker but never used. The computer tuning is going to be the biggest challenge for me. I have HP Tuners that I use for my LS builds but that does me no good for an OBD 1 chip. I already started looking into tunercat etc. The engine will be a 9.8:1 with speed pro pistons, an eagle crank, scat 5.7 rods and Blueprint Engine 64cc aluminum heads. I am going with the speed pro dish pistons I have because my Wisco pistons are flattops and that would put my compression to high. I had already ported the crossfire intake so I will stay with it. The one thing I probably will have to buy again is the cam because I think its to big for this build. The cam I have now is a comp cams 280H grind which is a .480/.480 lift with a 230°/230° duration at .050 lift. I had spec'ed this cam for a carb engine.I am thinking now that these parts are going into the Crossfire build I need to change grinds keeping efi and computer controlled in mind. Today I plan on finish pulling the engine and getting her stripped down so I can take it tomorrow to get boiled and bored,and bring the rotating assembly for balancing.

I am pretty sure they have computer friendly cams with more lift than that what you have right now. the lsa is what's important.

also you may want to look at tuner pro for your tuning or ALDLDroid.

I was actually looking at the Comp Cams 252XFI H13 grind that on their website it says "great for Crossfire" . That cam lift is spec'ed using a 1.6 ratio. The only thing I worry about is it puts my dynamic CR at about 8.7:1 which is a little high on pump gas.



I had seen that last night when I was searching its pretty cool. my problem is I have an iPhone.
Edit: I just downloaded Tunerpro but I dont see the definition file for an 84

I can say a 226/232 @.05 on a 114 lsa and 110 ICL works just fine. :cheers: 230/230 in a 383 is fine. Its just a matter of being able to tune the factory ecm or getting ebl or something.

If the 230/230 @ .050 is fine I will just stick with the one I have instead of buying another cam. I am going to wind up tuning the ecm anyway. I am staring to research my options now. I want to find something where I can data log using a wide band like I do with HP turners to better trim out the VE tables

Tuner pro let's you data log with a wide band. Ebl will do it in the wud too.