Hey guys, so I recently got my hands on a fully stock Vette a few months ago and I was wondering what you all would recommend doing to get it to about the 400-500 HP range. It is manual if that helps and there isn't really a money limit because I'm going to be doing all this as time goes on.
Any information is greatly appreciated.

 

-Install a LS3, or LS7
-Header with true dual exhaust
-5 or 6 speed Transmission.
-Dana 44 with 3.45 or 3.73 gears
-C5 Brake upgrade

 

If HP is your only goal, you may want to seek solutions beyond Crossfire injection. It is a challenging setup to improve, and reaching your goal of 400-500HP will probably require all of the following (and more): a step up to 383+CID, a tunable & properly-programmed ECM, larger injectors, stronger fuel pump, a vacuum referenced fuel pressure regulator, vastly improved heads and intake manifold, cooling system & brake upgrades, an appropriately sized cam, Dana 44 rear end swap w/more aggressive gears, headers & dual exhaust, black tag ZF or beefier tranny...and, of course, very deep pockets and the know-how to make it all work together as a system.


For a comparable investment, you'll find a lot more power potential starting at the ground level with a crate or junkyard roller cam engine which employs a more modern iteration of fuel injection. Swapping out just the top end on your current long block is also an option (though not ideal if your budget really has no ceiling--you'd be missing out on a roller cam, 1-piece rear seal, and potentially 4-bolt mains), as is abandoning EFI entirely in favor of a carb ().


Of course, it's not always just about power. I'm keeping the Crossfire because it's reliable, unique (many ditch it for the reasons above, or because Bubba called it trash), and I enjoy the modding challenge. That...and I don't have the time/$$ for a LS swap...but they're boring anyway!

 

If you Hog out all of the GM constricted BB holes they call ports. Upgrade to a 86 up fuel pump. Crank up your static timing to about 10 deg.
your 84 will be respectable. 500 HP is going to take serious parts. And eliminating the crossfire EFI. Due to lack up tuning software support. As above. Brakes will need upgrading to Stop.

 

Here is a great read for ya. Its in the C3 section but same CF motor.

https://www.corvetteforum.com/forums...solutions.html

 

That you do the work is going to save some cash. I don't know how much effort and money I want to throw into an old motor that might be tired. Considering that, It is going to take you about $15-20K to get a 383, trans, rear end gears and you are going to have to toss that ECM so someone is going to have to put in the ECM and have it dyno tuned.

 

Do you have to pass smog with it?

 

I don't believe a goal of 500 HP with an L83 Cross-Fire is realistic. A big LS motor swap, while complex, would be the more direct way to achieve a driveable 400-500 HP. My old 84 was modified with L98 heads, a ported intake, cat back exhaust, cam and Turbo City tuning chip and was properly tuned up. But with all that I was about even with a stock late 86 L98, say about 230 HP for the 86.

It was fun to drive but nowhere near 400-500 HP. You would also need more displacement, nitrous, bored TBIs, a greatly improved intake manifold and headers at least to get close to your target HP starting with a stock 84.

 

This is my sixth year of owning my '84 Z51. I've gradually been updating it and plan to continue to do so.

I've replaced the Star Wars cluster with a Vettaid analog setup and had a Tremec TKO600 five speed installed in 2014.

This year I am getting my money together for a LS1 swap. There's a Corvette recycler in my area that sells complete LS1 pullouts for about $3200 and up. I also found a complete LS6 from a wrecked C5 Z06 for $5000. That may be a bit much for me.

The last upgrades will be a D44 and front C5 brakes.

Good luck with yours.

 

...and I'm typically for modding what you've got. But that goal is lofty. The LOW end could and has been reached with a 383 short block, head, cam, different intake (but still a cross ram), bored TB's, injectors, headers, exhaust...basically nothing stock but still "crossfire looking". Ben73 is one, IDK his actual HP, but he was running low 12's and that takes about 400hp to accomplish.

500hp? Maybe you could do it with a "CFI looking" engine, but you'd be plowing new ground...that's for sure.

 

I wonder how close JoBy has gotten with that wild SCCFI of his

 

Yeah, I forgot about HIM. I think he was in the same realm, performance wise. He did good. That is one smart, resourceful guy there.

He's got so many killer pics on his site, but this one is pretty awesome;

 

That porting job is beautiful, he has blocked off the EGR valve with a plate so the EGR dongle could also be removed and that would both clean up the interior of the manifold and increase the plenum volume some. That is nice work.

 

I'm no expert, but have a few observations. I don't see where the OP was hoping to stick with the CF intake and TBs. Maybe I'm missing something? Assuming he isn't, then the choices open up quickly. The aforementioned LS swap is one way to go. However, that apparently isn't simple for a C4. So a useful alternative would be a stroker with good (and ported) aftermarket heads and a cam. Somewhere in the middle of his desired power range is easily achievable with known combinations. The biggest question mark would probably be the induction setup. He'd be looking at either a carb setup, or some form of standalone injection probably based on a single-plane intake converted to port injection.

To the OP, no solution to your goal is cheap or bolt-on simple. There's no obvious way for you to achieve your power goals with the stock long block or heads, short of a nitrous grenade (which would last about as long as a grenade!). But this is very feasible if you're willing to basically ditch the current motor and start over. I don't know enough about the older rear end housing or 4+3 transmission to know if you need to also replace those or not. My guess is you do. Let us know what you decide to do!

 

my porting job https://www.corvetteforum.com/g/picture/1347324 https://www.corvetteforum.com/g/album/1347303

 

I agree with many on this. A turn key solution is a full up LS swap. Along that is also other things like a ECU to work it, and I am assuming here that a stronger tranny if you have a 700R4. I reworked my 85 and I kept the orignal block but stroked, and cammed it. You gotta remember one golden rule here for internal combustion engines. more airflow (both in and out) is a good concept to follow. MatthewMiller was spot on in his reply. If you don't want to stroke it, then cam and heads on good bottom end is a good start point. Also you would be surprised how much better it will breathe with a better intake. Stealthram, Superram and Minirams can help here along with a some long tube headers.