Hillbilly method? Edelbrock 2701 Performer EPS intake and a 650 carb, with a drop base corvette aircleaner and lid. If you want to make it look factory, use a edelbrock 2101 intake and a quadrajet

If you feel like computer programming; some guys have adapted older carbureted dual-quad cross ram type intakes to the crossfire system by fabricating a new top plate for that manifold with the OE throttlebody system.

If you want to do something different; Stand alone computer and an LT1 will be great.

If you want to do something different, that is on-trend; any LS engine.

 

It's just a regular two barrel TBI engine with a fancy intake and two 1 barrel TBI's, all looks and no go.

Check to see what the head casting number is or at least the head material. These aren't bad as Swirl Port heads and not near as good a L31 Vortec heads.

Cam is roughly equivalent to the old 300 horse cam in timing with an advertised compression ratio of 9 to1 which for GM is usually a half to full ratio optimistic.

What you can do depends on the depth of your wallet and what you'd like to do. Basically there is nothing inexpensive that solves your problem. But most everything involves either spending for an advanced aftermarket injection system, a nearly equivalently expensive changing of the existing system and the injector bodies for a pair of the 2 barrel TBI's. Conversion to a standard intake with a simgle 670 CFM 2 barrel TBI from Holley or off a 454 pickup. The existing two 1 bbl TBI are capable of about 200 cfm each, a single 350 engine two bbl TBI is about 400 cfm. Anything involving fuel injection will require changes to the computer logic and will get into hardware changes that involve larger throttle bodies, injectors and ancillary equipment in wire harnesses, regulators, fuel rails, pumps, filters, sensors, etc. Changing the throttle body changes air flow capacity but not fuel delivery; changing injectors changes fuel delivery capacity; changing the programming changes the fuel delivered as a ratio to air delivered for each incremental change in power requirement from idle to WOT, coast to stop. The physical changes are coordinated with and by the software changes. The big limit on injectors is duty cycle they don't last when rum over 80% on time this plus fuel needs by max RPM sizes the injectors the program modifies to a lesser on time duty cycle for other conditions, fuel pressure is always constant. TBI is a low pressure system roughly 15 psi; port injection is at least twice that pumps and regulators are unique to either. This is not nearly as simple nor inexpensive as a carburetor.

The simplest way out is to ditch the crossfire and the injection system to be replaced with a decent intake like the Edlebrock Performer RPM and a Holley 4 barrel. If you stay with the stock cam and heads a 650 will be fine this will move your weak-kneed 205 horse at 4200 RPM to a more sturdy 305 horsepower at 5400 RPM. For more adventure a 750 combined with some head milling for compression a thinner head gasket GM uses .053 inch monster (there is a GM of half that thickness that will work) this will deliver 335 horses. Slip more cam into it of 225 degrees at .050 lift with an LSA of 110 or less plus better heads like the L31 or Fastburns or the many aftermarket modern heads and the RPM intake with the 750 carb can gun down horses in the upper 300's to lower 400's depending on tune details and be very streetable doing it.

Bogie

 

Seller told me it already has a cam, but didn't know the specs on it. Dosnt sound very aggressive at idle though.
It has larger injectors but I'm sure a stock tune.
It pulls hard in the lower rpm, but runs out of breath quick.
So, from the sounds of it at least a intake swap and good carb are in order.
Anyone done a similar swap? Is it possible to keep all the electronics working after the swap (digital dash, etc.)

If I go carb I'll probably do a vortec swap. Just did that on my 400sbc in my 69 chevelle, 062 heads, air gap intake. Went with steel shim type gead gaskets on that, deck hight was pretty bad but got my quench around .050-.055 area.

With vortec heads, performer intake (no air gap to help with hood clearance) mild-ish cam, 650cfm carb. Stock bottom end, and would have to swap to a HEI style distributor. What kind of #'s do you think I'd be looking at?

 

Doing the work yourself and this is very dependant on part selection for example heads run from about 500 to 2000 dollars a pair, intake from 140 to 500, a decent Holley from 450 to 700. So you're easily looking a 1200 to 2500 counting in the littler details of fuel pressure regulator, distributor, rocker arms, push rods the usual list of unknown details. Shopping hard on ebay and Craigs list using import parts here and there can help with cost management.

I think up front you need to get degree wheel and dial indicator on the camshaft to find out what's in there. If it's adaquate then you can save some money on a replacement, if not add that to the cost of parts above.

The 84 model was pretty simple in the computer, the digital dash just needs an input it already has from the transmission and a tach signal which can be had from an HEI ignition so that's pretty easy to solve.

The TBI fuel pump at 15 psi is a bit much for a carb but a bypassing regulator can be used to both bring that pressure down to a carb happy 5 or 6 psi and provide a return using the existing lines back to the tank to keep the pump cool and happy.

I'd hang onto the crossfire 20 years from now there will be people paying good money for them.

Check the heads to see what the casting number is and what they are made of. The lower end got an iron L98 head the upper end option engines got an aluminum version which is still used on the ZZ series crate engines.

The tranny is what makes this car exciting most came with a 700R4, that alone makes it attractive to give the machine the engine preformance that the driveline and suspension were built for.

Bogie

 

Biggest bang for the buck is a stroker 383 swap and a decent set of heads in the 180-190cc range and a set of headers.

You can put in the largest computer friendly cam you can find but the intake will hold it back so I wouldnt bother.

Zero deck the motor and run as close to 10:1 compression you can, quench tight as usual. This method retains all your existing components and stock look under the hood not to mention resale value and will likely give you an honest 50HP and 75ft/pds of torque down low where it really is felt.

If you really have the coin an aluminum 434 SBC swap is the best, takes a lot of weight off the nose and close to 100HP and more in torque...costs the most too. You can always upgrade the throttle body for more top end etc., lots of aftermarket stuff out there for that.

 

Ive owned an 84,,, You either change out the entire engine or accept meager gains on this engine. The heads do not flow much air even with a bigger cam.
Convert the dual tbi to dry air flow and use Edelbrocks intake and injector system, improved exhaust and reprogram transmission.
Dont expect much over 275 hp. The torque is quite good and the car drives great.

 

The catalytic converter may be restricting the exhaust even if its good you can get a little power just by removing it, the distributor advance is controlled by the brain and is a crap distributor, The cross fire intake is rare now and going up in value, and is actually very pleasing to see at shows, Usually its the injection that goes to crap on those systems and power is diminished over time put new injectors on and the engine will wake it up a little! The electronics are hard to work around to get any real power everything is designed for cruising and economy! Even with an engine swap or just intake and carb swap you still have the brain and electronic engine controls to deal with and the restriction of the cat! My cross fire Camaro Had pretty good cruising power but not good wide open throttle from mid range up, I pulled the cat and it helped a lot put in a HEI distributor with vacuum advance and centrifugal advance Kicked the timeing up and it helped more ! those are a few things to try But like Vinnie said don't expect much ! I wanted to put 2 Holley 500 2 barrels on the crossfire intake But just never got around to experimenting with it LOL I gave the car to my son! he drove a lot of miles and got great Mileage but used more injectors then oil LOL:thumbup:

Jester (Chris)

 

Consider a complete TPI intake, the torque producing long runners will make the most of the heads you have. With a stand alone speed density harness it's a easy install and will run your electric fans properly too. If you have a near stock cam you can simply use a OE calibration. Some headers, roller rocker and you wil near 260HP and globs of torque just off idle.

 

Oldbogie, I'm a bargain shopper. Won't buy unless it's a good deal. I think I have $300 into my vortec top end on the 400, and the heads are freshly rebuilt... Eddy carb is temporary, don't judge me. Lol



And yes, the vette being a manual is definitely a bonus, much funner to drive.

I'll look into what heads it has when I get back in town. Work the oil fields up here in Alaska so it will be a few weeks before I can look.

Just for fun, under hood pic on the vette. It's originally an AZ car that found it's way up to alaska.

 

dont need to look at heads. Those engines make 205 hp and they are all done by 4400 rpm. The stick is ok,,,ish. The car is great. Reread what I posted. That engine is limited to what power it caan make.Note the other fellas told you the same thing. If you want over 300 hp,thats not the engine to use.

 

What's wrong with the short block in these? Why swap the engine when I can just put a different top end on it? Swapping heads is easy, my only concern with that was keeping the digital dash, but from the sound of it the signal for the digital speedo is from the trans and not the ecu so I can do away with that and run a carb.

As far as I can tell and have read, the heads & intake setup is the limiting factor on these.

 

other than the crank and block,what else would you use?

 

Is there an issue with the factory rods, pistons etc?

They should have no problem supporting let's say, 300-ish hp?

I'm not looking to build a drag car out of this. Just a solid street/auto cross ride.


Idk. As-is it already has a cam, bigger injectors & a distributor. I may just port the intake & heads to try squeezing a little more flow out of it and call it good.


Seems I keep getting "just get a different engine"

Sure, I could go pick up a 350 or yank one from my other rigs, in the end they would end up needing the same work to make decent #'s.... So I fail to see how that would make a difference. Just like my 400, made tons of torque, ok power. Put fresh 062 heads, air gap intake, full length hooker comp headers, should be a sweet little sb now. Bumped the compression up quite a bit and way better flow now.

I guess what I'm saying, what's wrong with putting a better set of heads & intake setup on this engine?

TPI setup a are very hard to find and expensive when I do find them. This is alaska, we don't have amazing junk yards or tons of people parting stuff like that out like you guys have down south.

I still get a kick out of people talking bad about swirl port heads- no, there not great by any means... But my last pickup with a tbi and swirl port heads still made more power then this vette. Lol.

 

all the engine parts in that Vette are very well matched.All those parts combined make 205 hp.Youve had combos said that will get you close to 300(but less) hp.Computer programming has already been mentioned,,,
The block and crank is adequate. Rods? how many cycles on them? or miles on the engine made more than 30 years ago?Why would you spend a bunch on money on parts that will not support much over 300 hp?
so, other than crank and rods,what are you planning on using?

 

I agree with Vinnie completely. But it sounds like you're interested in a ghetto build (swapping used parts onto used parts), and it appears you've made up your mind mostly. There's nothing wrong with swapping a set of Vortecs and swapping over to a carb, but reliability, appearance and car correctness are out the window. Properly tuned though, and you'll be in the 300 HP range. Fight through putting a set of headers on the Vette and you'll be exceeding your goals IMO.

I have no idea what pistons are in your motor and you should figure that out and try to get an optimal quench. You should also try to figure out the cam number - pull it if you have to in an effort to find out what it is.

Personally, I'd go with the previous recommendation of swapping on a speed density TPI. The low end torque that it will deliver will put the driveability in this thing that you looking for (I think.) But I'm a TPI fan for street driven cars from my experience.


Good luck- Jim

 

does it start every time you turn the key????
does it smoke and burn a lot of oil????
does it use excessive fuel?????
are there puddles under the car after sitting over night, after running it all day????
does it drive and handle good????
did you change ALL fluids and filters???
did you clean the PCV system???
did you clean the throttle bodies???
did you do a full tune up on the ignition parts???
check ignition timing????


you might wanna start a new thread in the rear end/ tranny forum.
could jus be a gear change is all you need???? not a bunch of useless parts that you don't need.


IMHO,......... look into a gear change 1st.
I know, I know... THE MOTOR DON'T CARE WHAT GEAR IS BEHIND IT. but, the motor don't give 2 chits what size the tires are either. but tire size will matter when you want to get from 0-60 mph as fast as you can. same as gear ratio.
you want more fun, more torque, more acceleration from a 205hp sbc, on the cheap???
PUT MORE GEAR BEHIND IT!!!!!!

 

64nailhead, as has been stated already TPI setups are pretty darn hard to find and expensive when they are for sale here.

Used parts means a ghetto build? Sure, why not.

Jax pap, many roads here are perfect for high speed driving, many of us cruise at 85-90mph in areas. I'd think going to a deeper gear would probably put a hurting on that kind of driving.
Have I checked all those things? Nope. Iv put maybe 20 miles on the car and am disappointed so far. It's pretty sad when my truck that's on 35"s feels quicker then my vette though lol.

 

64nailhead, as has been stated already TPI setups are pretty darn hard to find and expensive when they are for sale here.

Used parts means a ghetto build? Sure, why not.


Have I checked all those things? Nope. Iv put maybe 20 miles on the car and am disappointed so far. It's pretty sad when my truck that's on 35"s feels quicker then my vette though lol.

'Ghetto build' is the term used in our neck of the woods and I probably shouldn't put it in writing because it isn't considered politically correct. Oh,,,,,, wait a minute, I don't give a flying rat ***** about being politically correct. I'm not implying there is an issue with building it, it is only a term.

We also use ebay down here and we generally can find most anything no matter the location - we just get it mailed to our home. I would guess the same postal service delivers to locations in Alaska as well. Regarding the price, for less than the price of 2 of your 35" wheels and tires you could get it running on your Vette.

I'm not trying to be sarcastic sounding, but you posed a question(s) on this forum and you've been supplied several viable solutions. You have refuted every solution that has been offered up.

Best of luck to you - Jim

 

Well, I ended up picking up a L31.
Couldn't pass it up for $100!
Plan on a simple rebuild, cam, intake & carb with hope of around 350-400 crank hp.

Anyways, here's a vid of the vette!
https://youtu.be/1iNaESMc97Q

 

are you going to do a stump rebuild as Richard would say? Or are you doing it right?