Should I swap or build the 350 motor in this old vette?
Posted by ARandomGlassOfWater@reddit | projectcar | View on Reddit | 51 comments
Motor is giving me some trouble running normally after this car was sitting for a long while. I love this style of corvette and I really don't wanna get rid of it so whats something fun I can do with it?
v8packard@reddit
This is going to be flamed.. Would you consider a big block?
I used to think a 454-based engine in a C4 was a bad idea, until I built one for a customer and drove the car. It handled better than I thought, and was one of the most fun driving cars I have ever experienced.
Having said that, if you are considering a swap to a LS, consider the cost of doing a complete swap then imagine the small block you can build for that price.
Why not fix whatever is wrong?
Busterlimes@reddit
Yeah, on a serious budget your are probably looking at 10k min for an LS swap.
v8packard@reddit
Very realistic
Busterlimes@reddit
My brother spent 20, but he bought a Holly Dominator and hopped up the cam and some other stuff when he swapped his 92 Camaro. That was also with a Trans.
v8packard@reddit
I have been involved with a number of professionally done swaps where the tab was $20-30k.
iFunny-Escapee@reddit
DAMN, how do you build up a tab that big with an LS swap? Is it all the fabrication needed?
v8packard@reddit
What are labor rates by you? In northern Illinois, a small town Chevy dealer is $220/hour. What's fair?
Let's say you have a parts tab of $12k. I have easily seen the parts tab at $12k for a basic 6 liter swap into a Blazer. Add in 80 hours of labor at a rate of $100/hr. You are at $20k. You have a complete, running, driving swP. Everything works. Ready to go. Does that sound unrealistic?
iFunny-Escapee@reddit
When you put it that way, that sounds pretty fair and straightforward. Fair enough
v8packard@reddit
There is this perception that you can get a $500 LS from a junk truck, buy a cheap cam, and put in some vehicle that never had a LS engine, and you are driving a 500+ hp car for no money. But, it's just not realistic.
Squidking1000@reddit
I would never flame someone for suggesting a BB. Why the hell not! After all there's no replacement for displacement!
Syscrush@reddit
Volumetric efficiency has entered the chat.
RBuilds916@reddit
Yeah, LS motors are turning out numbers that used to be the domain of big blocks. With a smaller package and lighter weight, probably better fuel efficiency. I'm not sure what the cost comparison is, but you have to want an absurd amount of power before the big block becomes necessary.
KdF-wagen@reddit
Thats why you add a blower!!
everyoneisatitman@reddit
A aluminum headed 11:1 compression 454 with an semi reasonable roller camshaft with a single plane intake matched to a tremec would be the most amazing vette ever. I have only ever driven a VERY stock 80s vette that was supposed to make aroumd 240hp new. Having a built big block in it would be the closest thing to owning a portal gun. What were the header options for a BB in a C4?
v8packard@reddit
We modified some C3 big block headers, started with 1 3/4 tube Hedmans. The engine really needed 1 7/8 headers, but we were worried about fit.
NuclearWasteland@reddit
"Some trouble"?
If it's running weird from sitting it's the fuel system. Clean that, and injectors, as modern fuel has alcohol that pulls in moisture and messes things up as a result.
If that sounds like a pain, I would not recommend an engine swap.
ARandomGlassOfWater@reddit (OP)
I just replaced the fuel pump and tank and filter. Gonna try to clean fuel rail next. I want this thing to be a sort of street legal track car so I was planning on ripping out a bunch of parts from the engine bay and interior that I don't need. Figured if I'd be stripping the motor down I'd might as well consider a swap. Honestly I've never pulled a motor before but it's a project car for a reason and I'd love to waste my time and money on it.
clockworkblk@reddit
Put a cheap clear one on the inline filter. Thats been a cheap troubleshoot for me in the past, so you can see if it starts before the engine or not
NuclearWasteland@reddit
I mean, if it's a clean example, you might reconsider getting a rougher one to learn on.
I've had a lot of vehicles, and while I learned along the way tearing apart the nice ones I'd have learned the same or more doing so to a beater. Looking back, I destroyed some nice cars, and regret that.
These are at the bottom of their market now, but will not stay there. No Corvette does.
Ultimately it is your car, enjoy it however you please.
aBuzzedLife@reddit
My grandpa had one just like this. I believe it was an 84?? I loved going for rides in it as a kid and was pissed when I found out my uncle sold it just before he died earlier this year. Super sprint exhaust sounds real nice on these cars 👌
LoseyMcLoseFace@reddit
What year C4?
If its an 84, your call. Not a fan of crossfire.
If its an 85-89, the L98 is honestly really fun as-is when its running right. That tuned port injection is some reliable stuff if its maintained and makes really fun torque. Id just get it running right and enjoy it as is. I had an ‘87 for a while and I loved it.
StartwithaRoux@reddit
Depends on what you want to do with it. Define the end goal. Are you going to just cruise this thing and occasionally push the right foot down? Or are you going to do auto cross, drag, back roads stupidity?
If you're occasionally going to push the right foot harder and cruise it.... throw a cam at it and maybe some heads, tune, call it a day.
trailing-octet@reddit
OP - lots of great advice already given here.
I’d be an LS swap kinda guy in general, but in all honesty a nice rebuild of L98 to a 383 with heads and some fancy standalone ecu work etc. is probably going to be easier on the whole and easier to stick to a budget on. It could definitely deliver a massive improvement over the oe 350 with lots of pep on tap in the 1500-6000 rpm range while appearing (but not sounding) outwardly damn near stock.
BabiesatemydingoNSW@reddit
Yup. A 383 property sorted will make over 400hp and a mess of torque.
Agent_Eran@reddit
Well over 500hp
IntheOlympicMTs@reddit
Depends on why it’s running funky.
Mrid0ntcare@reddit
Check the drain inside the fuel door make sure it isn't clogged. These vettes like to accumulate water there and it gets into the tank.
dethroned_dictaphone@reddit
If it were me, I'd try to think of the swap that would not only make better power but also make the most people hate me. 2JZ and RB26 spring immediately to mind, but maybe going smaller would be fun, like a K or a VAG 20V... Or go really nuts and do a 13B.
Then I'd ponder it for a while and just fix the 350.
trolllord45@reddit
Swap. Could probably drop a much more recent engine in relatively easily with the availability of LS based engines and parts
Agent_Eran@reddit
Fuck an LS swap. Waste of money for same performance
v8packard@reddit
I suspect many people that down vote this have little experience with real swaps.
Agent_Eran@reddit
yup! Its the reddit way!
big ol echo chamber.
They will downvote but cannot respond with anything of substance
boostedmike1@reddit
Resto mod
secondrat@reddit
Keep working on that motor. If you want something faster go buy a C5.
Keep going through the fuel system. Those L98s will run forever, but anything that sits for a long time will need lots of stuff replaced.
Agent_Eran@reddit
C4s go fast too
Gavovision@reddit
Go big block
HarlanCulpepper@reddit
unrelated fun story :
Had a crazy mean neighbor lady with more money than brains. She bought a brand new red '86 - "in cash", she bragged.
Well she should have test driven it to her house with an unusually steep driveway to her garage.
Every time she pulled into or backed out of her driveway, she'd bottom out - hard - the front and rear of that poor car.
She pretty much destroyed it in less than a year and traded it in on a brand new convertible Z28.
Guess how that went.
NuclearWasteland@reddit
Well, owning an F-Body I'll guess ground effects becoming microplastics and saggy door hinges, lol.
HarlanCulpepper@reddit
Yup!
sladebonge@reddit
Is it the original engine?
smthngeneric@reddit
Who cares. If he's really worried about resale, he can set it off to the side. No one cares about numbers matching except old guys who want to relive the glory days
Squidking1000@reddit
Especially in a C4. They are the cheapest corvettes for a reason, millions made and none are really all that great as far as performance.
smthngeneric@reddit
No corvette up until the c6 is really that great at performance from the factory, that's why the aftermarket exists. You can make them actually live up to the hype of a corvette
Squidking1000@reddit
Which is why you shouldn't worry about "numbers matching". Honestly I think "numbers matching" is stupid for anything but the highest echelon of rare cars if even that. I love people posting base 350 firebirds with "numbers matching" drivetrain. WOW numbers matching 2bbl with a powerglide. Who gives a shit?
DmOcRsI@reddit
I just got done building a 383 L98... the problem is on those motors is the intake runners are too long... but, all the aftermarket support for those things dried up years ago, so the intake manifolds that used to be out there are selling for a really high premium. I used AFR Heads and a good cam, but I couldn't get away from that intake manifold and it'd fall on it's face after 6,500\~7,000RPM. Torque monster, but honestly not that fun to drive.
However, I'm in California and my whole point was to try to keep it as CARB Legal as possible... the AFR Heads were stamped CARB, the headers were also CARB legal... if I was outside of California then I'd of had a better intake manifold but that would of required a cowl-hood and in my opinion that wouldn't look too good with the rest of the car.
BurritoBandito8@reddit
If someone is neck deep in a 383 stroker build, a premium $$$ intake isn't going to stop or persuade them. And I agree, keep the stock hood if possible.
DmOcRsI@reddit
This was a build for my father who loved C4's... he wanted to keep that stock motor in there, I just did the work and advised him on the build. If it was me, then I would of dropped in an LS3 w/ the 6-Speed and had it BAR'ed to get smogged.
juwyro@reddit
Figure out why it's running weird now or that problem could follow you to the next motor.
largos7289@reddit
L98 motor i think that year. They are great little stop light warriors, my 86 vette was built right as they made the switch to the aluminum head version. I loved that thing. Me i would build the L98 up, don't LS it, everyone and their grandmother does that shit and it's really f**k'n old now.
meata@reddit
Depends on your level of ability but a 383 build is a good cheap option if you have time and space to put it together yourself
Carbonbuildup@reddit
What year is it? 84 or 85-7?