Hey everyone. I've had an 84 that's been out of commission for a few years. My dad and I want to throw another engine in it this year and get it going. Problem is, funds are limited, as is my dad's knowledge of newer engines. We're thinking of going with an older SBC 350.

What would be our best options? I plan on getting a new carb, manifold, cam(unless stock happens to be good), etc. and I've heard some of the older engines will only bottleneck the power. We'd also like to avoid a PCM. Hope someone can help me out! Thanks.

 

1981 301 4.9L with a turbo

 

Thanks, I'll take a look at that one. I've heard the L31 Vortec is pretty good. I know there's a manifold you can get to use a carb. Any thoughts?

 

The carb and distributor (along with the ECM) are fine for a mild 350 build. A cam upgrade in an L31 would make for a nice runner. However, if you use the L31 heads (which are pretty good heads), you'll need to upgrade the valve springs (search on Vortec heads and valve springs), and the intake manifold you get will need to be for Vortec heads.

Since the 301 turbo meets absolutely none of your criteria (except possibly the no-PCM part), my recommendation would be to completely ignore that response.

 

Times 2

 

a carbed vortech with a cam and spring upgrade would do wonders for that car

 

Excellent, thanks guys. Would the ECM be required for that engine then even with a carb build? We want to make sure we can finish the project we start without any major snags. Plus I'd love to get this done for no more than around $1200-$1500.

 

i did a budget built 350 with numbers around 370 horse and 405 tq for under a grand, not too hard to do, find a low milege complete motor, any years will work, but the 87 ups would be nice to build efficient power with a roller cam, when my 305 tpi finally saw its last breath i tore it out, took the heads, and had those completely redone with hours on hours of my own time porting and polishing them, everyone says vortec heads vortec heads but they are as crack prone as any other head and offer u only .450/.460 lift max until u run into issues unless u only wanna make like 340 horse max. or spend a few hundred extra getting the special stuff for the vortecs. i had a better set of heads to use for my setup some 034 casting bowtie phase 2 heads but with my motor coming factory dished pistons it wasnt an option, since i woulda been rocking only around 8.8-1 and a 244 duration cam is not going to like that at all, so opted out and redid the tpi heads, spent around 350 bucks getting them all redone, and got some hardware for cheap matched to my cam for 50 bucks, springs, locks, and hardened retainers. if u can find a set of vortecs for cheap go that route, depending on what kinda power u wanna make, most newer blocks will come equiped with flattop pistons which with the vortecs 64-67cc combustion chamber will give u right around 9.5 to 1 and with enough duration safe to run on 87 octane

 

Thank you! Is it possible to do a newer 350 build without a PCM/ECM? That's a big factor for us. We'd like to do the least electrical work as possible. I'm not too concerned with getting every last bit of horsepower. I just want a fun car to ride around in, while hopefully not getting terrible gas mileage.

 

Define "Newer".

They stopped doing carbs in motors in the late 80's except for a very few rare models into the 90's.

Get a vacuum controlled distributor, a NON Computer controlled Qjet and there you go. 84's were pretty dumb when it came to computers, won't even miss it if all the rest is disconnected as well. However, if you have/want the electric fan to work, you'll need to leave that circuit hooked up, as well as AC or any other accessories if you're even worried about those.

My 84 has a motor in it from a 1998 Silverado that was in a wreck. Everything from my 84 305 bolted to the 350 from the Silverado with zero issues. I had only to upgrade from a 305 knock sensor to a 350 sensor and re-tune the carb for the larger motor. Otherwise, it was as plug and play as it gets. And I kept all my computer controlled goodies, like the computer controlled carb, AC, cruise control etc.

 

if thats the case, then yeh try and find some vortec heads, or maybe even some older camelbacks, u see those from time to time on craigslist for a decent price, and put in a cam with specs around .450 and maybe 218 degrees duration, should make around 325 horse with a 600 cfm carb, maybe a 650, (but u can always jet up a 600), isnt too much wiring involved, i went mechanical gauges to make even less wiring, and yes all small blocks with 1 piece mains can be turned carbed just as easy as the older ones, i think some may not be setup for mechanical fuel pump however, dont quote me on that lol, but electric with a 7-8 psi regulator works too, only ones you cant are the lt/ls based blocks those are a totally different platform from the gen1 and II's. the most wiring involved is removing the wires, theres wires everywhere for the tuned port setup, u just need to figure out all the wires u need for your ignition and starter, and ull be alright, and alternator ofcourse, really simplifies it. only downfall of goign the vortec route is your not most likely not gonna be able to find used vortec style intakes for cheap, most likely gonna need to buy new, but if you and your dad are the ones building this engine u can still keep it under 1200

 

You are correct about the fuel pump. The one I got from a 98 came with the mounting points for a mechanical pump, but it was not "drilled" for the pump rod. I wound up installing an in-tank electric pump using a painless fuel pump relay kit. Basically, you want any Gen 1 style small block. From 87 and up they went from flat tappet design to roller, otherwise they're identical.

Vortec heads were the best heads GM EVER made for the small block chevy motor, until they came out with the LS motors which were a complete redesign. Stay away from the camel-hump heads. They were great for their time, but stock casting L98 heads from our 350 TPI cars easily match them now.

 

yeah if u can find some tpi 350 heads casting "083" those are some of your better stock heads and flow great on the intake side, exhaust side needs some severe porting on those heads, and i wouldnt reccomend learning on a set of heads u wanna stick on your car anyways, i learned on some old no name crap smog heads till i got the hang of it, i just threw camebacks in there because they are a durable heavy casted head, and alot of times u can find them done up, sometimes too far done up though for a mild build you are looking to do. do u have the heads from that car, and if so what casting numbers are they? those might be decent especially if it was a 350.

 

You aren't thinking this through, or are getting bad information.

You won't have to do ANY electrical work to keep the factory carb/distributor/ECM. NONE! On the other hand, if you convert it to non-computer and have an auto transmission, you WILL have to do some wiring work! Among other modifications that may not be of a wiring nature, but can be frustrating none the less.

You said funds are limited - then don't waste money on stuff you don't need! The factory computer carb is the best street/performance carb out there - bar none. If you want a fun car to ride around in, that doesn't get terrible gas mileage, then the stock carb IS THE ONE TO KEEP! You won't have to do anything to the computer itself.

You need to get over whatever is leading you down the wrong path. People are too quick to abandon what works because they assume it isn't as good as what hot rodders did in "the good old days". Well, for one thing, those days weren't all that good. I was there. Get all the information before you let yourself be led down the wrong path.

Now, let's talk bottlenecks. If you get an L31, the bottleneck will be the factory valve springs. If you have the base LG4 engine, the bottlenecks will be the single snorkel air cleaner and the exhaust (all of the exhaust). A dual snorkel air cleaner will solve the air in bottleneck, and headers, Y-pipe that's 3" after the 2 sides join, and a 3" cat back (take your pick - as long as it's got nothing smaller than 3" before the muffler inlet, it'll be fine for a mild 350).

 

i was just giving him that information because it sounds as if he wants to build an simple, old school motor, at a really cheap price tag

 

A grand, huh? A vortec motor is about $500 alone on the low side. Air gap is like $250. Carb is $200+. cam/lifters/timing chain $500. Budget already broken?

 

And I'm looking at the best path the desired final product with a limited budget.

 

I really appreciate all the info here. I'll supply a little more backstory. The car is a few hours away at my dad's place. Up until recently we hadn't spoken to each other for a couple years, and I haven't seen my car for at least that long.

My memory is pretty lousy, and I haven't done any research on this until I started this thread. I've never done an engine swap before if that wasn't already obvious, lol. I honestly can't remember if the 84's already have an ECM in there. But it sounds like going up to a 350 would be pretty easy and I won't necessarily need to change a lot of the parts. Let's say I went with an L31. Does it more or less bolt right in then and work with most of the existing parts?

I'm all for making this as easy as possible. I really do like what I've read about the L31's. And again, thanks to everyone here for helping me out. I still have a lot of gaps in my knowledge, but everyone here is helping a ton.

 

i got a edelbrock performer off craigsist in nice shape for 75 bucks, a edelbrock 1407 (750) from my buddy for 165, that was matched to the cam i got from him, that was 50 bucks and the hardware, another 50, block was a .60 over 1973 2 bolt main outta a truck my friend sold me for 50 bucks because his family was moving to kentucky, gasket set was like another 50 bucks, head work was around 350(mostly time consuming with all the porting and polishing), lifters were 50 bucks, i spent a little extra on peformance bearings, cant remember that price, and i already had most of the little stuff needed, it wasnt something i gathered parts for over night, just slowely got everything in the amount of about 4 or 5 months

 

and who needs to buy a vortec motor, a tbi is just about the same thing with different heads, and u can find those all day with the head problems those have.

 

buying the heads seperate on a non complete motor is most likely gonna be cheaper, when someone is selling a complete vortec motor they put a giant price tag on it

 

i know a company that makes aftermarket vortec heads, they all called EQ, my machinist swears to them and i personally know they are legit because my buddy ran them on his 485 horse 383, with no issues, and a thicker casting than oem vortecs with i believe 170cc intake runners and and true 64 cc combustion chambers, comes with 2.02 intake valves and can be had assembled for around 250 a piece, if u can budget the rest of your motor these would be a better alternative than stock vortecs, which stock vortecs are nice but these outflow the stock ones and are a thicker better casting, ive never liked vortecs too much because all the issues they have with cracking from people deciding its healthy to run a motor at 260 degrees for long periods

 

may have been closer to 300 a piece assembled, i cant remember almost opted out of redoing my tpi heads and getting those but it was still cheaper since i would have had to spend 140 bucks on some decent hyper flat tops and another prolly 120 getting them pressed on my rods, but bottom line is those eq heads are real nice, worth the investment, if u can budget build around it, i personally wouldnt buy a complete motor without going through it, but i know many people who have found a complete motor and just put better heads and valvetrain on it and had it work wonderfully.

 

and the cost of a rebalace also, ive never priced that out

 

Thank you. I'm looking at some other options right now. Any opinions on the L05? Price range is a lot more reasonable. It would definitely allow me to upgrade it more than the L31.

What would be the bottlenecks? Any thoughts on what I should immediately look to replace/upgrade would be much appreciated.

 

the first thing i would do is go check out what shape the car is in currently make sure there arent other issues that should take precedence over building a motor. As for the motor i personally would redo any motor that you put in, it would suck to do a motor swap and have it put a rod through the side two weeks later so budget in machine work. I would personally look for a late 80's early 90's roller cam block get it checked and/or bored and assembled from the machine shop and put as set of whichever heads you decide to go with on it. This is probably going to put you over the 1G price tag but is well worth the investment for years of driving fun. Just my but hope you will think this through and do it right the first time it is cheaper in the long run

 

Thank you. The 305 in it now is toast, so a new engine takes priority.

 

The shortblocks are basically the same, true. But, if you're buying an engine, and budget is an issue, then you probably won't want to go with aftermarket heads, or buy an LO5 engine for the shortblock and then buy Vortec heads to put on it. If you're not looking for the last little bit of power out of the 350, the the LO5 with its swirlport heads would be just fine. I don't know where you're getting your information about "the head problems those have", I've never seen one with an actual head failure, but have seen several with crank bearing failure (and that goes for L31 engines, too).

Okay, about the computer - Unless this car was delivered in Canada, it will have a computer. Replacing the stock computer-controlled 305 with a 350 will involve unhooking a couple of more electrical connectors (marking them as you disconnect is a VERY good idea) and a couple more sensors. That's all. Everything will transfer from the 305 to the 350. As I said before, converting to non-computer will be a lot more electrical headache.

 

Perfect, thank you. I'm fine with leaving the existing computer in there. I wasn't sure if it would mesh with a new engine, so that's good. I'm not opposed to spending a little extra for new heads, especially if I find the engine for a reasonable price. Would you have a recommendation on the best value for price/performance on some new heads?

 

For what you've described as goals for this car, with a mild 350 (cam lift .440" or less), in my opinion, you cannot beat this kit:

https://sdparts.com/details/scoggin-...nter/sd8060kit

If you want a little more cam, or something just a little better, for only a few dollars more is this kit:

https://sdparts.com/details/scoggin-...ter/sd8060akit

 

Excellent, thank you. I've done a lot of looking around but don't really know what I'm going to do yet. Depends what kind of engine I can find locally and for what price.

I'm assuming the 700r4 would work fine with any 350?

 

Heres the best info I can give you. Get a used engine from a wreck 86-91 Corvette. Use your stock manifold and hook everything back up. Buy Dyno Don Headers and a 3in cat back exhaust. No computer tuning needed then enjoy the car. Simple!

 

700R4 will bolt up to any 350 mentioned in the previous post.