Opinions wanted, to swap 305 out or not

[JesseSimon]

My '77 LWB came factory with a 350, somewhere along the road somebody swapped in a 305. I can't wiggle my fat *$% in to make out the casting number but I can see a stamp that reads GM 5.0L LG or possibly L6.

The motor has HEI ignition and it starts up everytime and runs great but it lacks any get up and go. I'm not saying the motor is damaged and weak from wear, just that it isn't powerful at all. Anyway, I have lots of leaks in the drivetrain and I am going to pull the motor and trans to re-seal everything. Between the motor oil, transmission fluid, and power steering fluid, my driveway looks like Deepwater Horizon, it's bad. Exhaust leak too!

My question is, if it was your truck, would you do the work on the 305 or would you find a 350 to throw in it while the motor was out? I don't have much money, but there are trucks on the cheap here in the Ozarks, I see similar LWB's everyday between $500-$700 in good running order. I could realistically buy a donor for its motor and sell this 305 without expending much in the end....

Any opinions? Any 305 fans that wanna take up their case?

[78 Chevyrado]

350

[dswancutt]

I think it all depends on what you are going to use the truck for. True, you could find another truck with a 350, but you do you really know what you are getting?
When the 400 in my 78 4x4 took a lobe of the cam, the only thing I could afford at the time was a used 305 out of a 81 or 82 blazer. That was over 10 years and god only knows how many miles ago and it is now just about shot. True, it has no power, even with 3.73 gears but it served me pretty well.
If it doesn't use oil and is reliable, just put a gasket kit on and run it until it dies.
Just my two cents worth.

[nbpro]

Originally Posted by dswancutt

I think it all depends on what you are going to use the truck for. True, you could find another truck with a 350, but you do you really know what you are getting?
When the 400 in my 78 4x4 took a lobe of the cam, the only thing I could afford at the time was a used 305 out of a 81 or 82 blazer. That was over 10 years and god only knows how many miles ago and it is now just about shot. True, it has no power, even with 3.73 gears but it served me pretty well.
If it doesn't use oil and is reliable, just put a gasket kit on and run it until it dies.
Just my two cents worth.

x2

[C-10 simplex]

How much faster is a stock 350 going to be compared to a stock 305? i'm not talking about modded, crate, or corvette 350's, i'm talking about stock 350's.

Do you think it's worth the hassle and cost of a another engine just to get .4 seconds(if even that much) faster 1/4 mile time?

Not a good move in my opinion.

[JesseSimon]

I dunno jack about motors haha. So I have no idea the difference between a 305 and 350 as far as power. I'll probably stay with the 305, looks like a seal kit is pretty darn cheap.

[mokelife77]

if your short on cash like me,id stay 305,my dad runs a bone stock one with just a cam,performer intake and a holley 750 with 150 shot nitrous in his 79 camaro,and its the most reliable motor we had,been running great for the past 6 years(he only uses it to race) that made me gain alot of respect for the little ole 5.0 we got for 200 bucks with like 150000 miles on it..

[79gmcc15]

I am building a real budget rebuild. At this point I am at about $340 and lots of work. http://67-72chevytrucks.com/vboard/s...d.php?t=408210

yes a 350 is a better platform for power and by default it will move the truck easier. and the cost of building a 305 vs 350 is just about the same. But, if you are low on money. It would be in your best interest to rebuild your ole 305. It is just as reliable as any other small block. And a 305 with a couple upgrades can make almost as much as a bone stock 350. I am going to enjoy the heck out of my 305.

[spudz]

keep the 305, they are damn good and get no respect.. Make good power for the displacement. get ya a stock replacement cam for a 350 and install, put some 1.6 rocker arms and stick some 373s in the rear and you will smoke ANY factory 350 equiped stock 77 pickup. maybe even the 454 trucks....

[spudz]

oh an new timming chain. the stocker should just about be shot.

[JesseSimon]

Thanks for the advice guys.

[3r!c84]

hey the 305s are pretty good motors pushed my truck into the high 16s and can blow away almost any stock 90s 350 trucks



but who am i kidding im about to put a pretty healthy 400sbc in its place

[old Rusty C10]

I didnt read everyones response but a 350 and a 305 will interchange... id buy one of those donors and swap motors and sell the donor truck or just part it out

[jrcaprai]

Personally, if you could find a good 87 or newer 350, they all came with Hydraulic Roller Cams... gives you a few more options, plus they come with the Single Main Seal, rather than the leaky 2 Piece Seal... a 350 over a 305 is good for 35-50 HP and about 50 Ft-Lbs torque, just by increasing the Displacement alone.

[benoit454]

normally I'd say 350 or nothing but we got a little 305 that sure made a beleiver out of me. It came from dad's 84 c10 and it's now in the 85 mcss I sold to my brother in law, and it ran awesome in the truck for a 2.73 rear gear and it'll smoke the tires as long as you want it to in the mcss with 3.42's Both ran th350's and the monte has a stage 2 shift kit and barks tires hard going to 2nd and can get some chirp going into 3rd. I ran a 350 in the mcss when I had it and it's now in the 84 c10, and the mcss does better with the 305 in it, however I had a 2k stall in it before with a 350 and it would barely break em loose, I think I got a junk converter. Now with a stock 305, just long tube headers and an edelbrock with a stock tc and that stage 2 shift kit th350 it screams as mentioned above. I aint rode much in the truck with the 350 in it now and a stock TC so I aint sure how much better it seemes to run now compared to when it had a 305.

I do know that same 350 in a 76 that had posi and stick shift it was nasty, you couldn't keep it from burning tires off, but I think it had a good ratio like 3.73 or 4.10 or so.

I think I'd stick with a 305 if cash was tight, rebuild and maybe torquey cam and intake and maybe carb swap with headers, if not and you can get a donor with a 350 go for it and as said build another truck or part it. I'd buy a parts truck put the 350 and any other good stuff on yours, put your junk back on it and sell it whole.

[Davidmichael]

I would say if you are looking just at a budget, and doing all the work yourself, if you can find a good running donor truck cheap, do it. Swap out the motor, then maybe you can get ahead by either parting it out or selling the whole truck outright. If not, then build the 305.

My personal issue is I had a 305 that was put in my truck and it blew up with in 2 weeks. I had a 350 put in after and it's still running strong. Just that little horsepower makes a big difference. I also have a Olds 307 in a car I have and it's on the second motor. It's too small of a motor IMO to a fullsize truck or even a boat of a car like mine.

[motornut]

having swapped a few truck 350s in for 305 in cars,my choice would be 350.if your putting money into the 305 block, change what you can to 350 parts,if she blows then hopefully the parts would still be good for a 350.If you are on a budget making your gas mileage get worse for performance dosn't help you.But if the 350 is something you want in there,sell the leftovers.....................i did put a 350 cam in a 267 (79 olds)and what a difference that alone made.....and i had to put a 305 from a monti into my burb a while........but that won't happen again lol

[Pop's C-10]

i agree with dswancutt

[bwood]

Originally Posted by jrcaprai

Personally, if you could find a good 87 or newer 350, they all came with Hydraulic Roller Cams... gives you a few more options, plus they come with the Single Main Seal, rather than the leaky 2 Piece Seal... a 350 over a 305 is good for 35-50 HP and about 50 Ft-Lbs torque, just by increasing the Displacement alone.

Hyd Rollers were not standard until 96 with the Vortec engines. It happens but it is rare to find factory equipped roller in the TBI engines (87-95). All of the blocks are drilled and tapped to accept the stock roller cam equipment, but most truck TBI engines came with hyd flat tappet cams.

To the OP, you say you can see 5.0L on the back deck of the block, you may already have a newer one piece rear main engine. When they changed the block design to the one piece rear main seal in 86, they added the displacement in Liters in the block next to the casting numbers. If this is true, you could add a factory roller setup if you wanted.

As far as swapping to the 350, I would only do it if you had the $$$$ or the 305 was a goner. Its getting you around now, it just needs some maintenace. Fix it up, clean it up and run it until it won't go anymore.

[79gmcc15]

My 84 305 has 5.0 L stamped and it's a 2 piece r.m.s.

[jrcaprai]

Originally Posted by bwood

Hyd Rollers were not standard until 96 with the Vortec engines. It happens but it is rare to find factory equipped roller in the TBI engines (87-95). All of the blocks are drilled and tapped to accept the stock roller cam equipment, but most truck TBI engines came with hyd flat tappet cams.

Guess I should have not been quite so general with my post... I was not just talking about the truck engines only...

87 is when GM started to use the one piece Main seal and 1988 is when GM put the 350 roller-cam engine in Camaros/Firebirds, some Caprices, and some ¾-ton trucks... Thats why it's hit or miss with the trucks...
I see roller cammed 350's quite often for sale in my area usually between $500-$1000

[junkyardjohn]

JUST MY PERSONAL OPINION... BUT I WOULDN'T INVEST A GASKET SET IN A 305. I BOUGHT MY 84 4X4 FROM THE ORIGINAL OWNER, WITH THE ORIGINAL 305 IN PLACE WITH OVER 300,000 MILES ON IT. IT WAS TIRED & CRIPPLED. AFTER ABOUT 90 SECONDS OF CONTEMPLATION, OUT SHE CAME & IN WENT A 72 350. ALL THE ACC. INCLUDING INTAKE & EXHAUST STAYED & BOLTED RIGHT UP. NO EXTRA WORK & NO EXTRA $. BUT THATS JUST ME.. YOU KNOW WHAT THEY SAY ABOUT OPINIONS. JOHN

[Slonaker]

Originally Posted by jrcaprai

87 is when GM started to use the one piece Main seal

One piece rear main started in 1986. Center bolt valve covers started in 1987.

Slonaker

[jrcaprai]

Originally Posted by Slonaker

One piece rear main started in 1986. Center bolt valve covers started in 1987.

Slonaker

You are Correct sir, one piece in 86, then roller cam block in 87

[78 Chevyrado]

Basically if you have a light truck, want more MPG and don't live anywhere too Hilly, go with the 305. Otherwise go with the 350.