I know there are a lot of threads about this. I am saving for a wedding so I am on a budget. I wanted to add power to my 305 but I read that its not worth it, yada, yada, yada and people telling me its garbage. I was thinking of doing the whole exhaust since I got the flowmaster 40 series. I had to change the distributor bc it was shot so I got a Msd which was well worth it. Anyway I enjoy driving the car even with the 305. Should I just save for a 350 and then by the bolt ons? Or buy some bolt ons for the 305 and stick with that for awhile until that goes? Please be honest, be brutal if you have to lol.

 

depends what you want... if you really want to beat any cars out there. or you want to do any track or drag... save up for a 350.. if on a budget and you are not competing and you are not a hot headed racer.. stick to the 305... treat her well.. put in a lt1 cam and open the exhaust.. plus you get good MPG with the 305

 

Alot of the same things that you would do to a 305 to help it out, will help a 350 as well.

Furthermore, alot of the things that are making your 305 even slower than it really has to be, will also cripple a 350.

Just yanking out a 305 and dropping in a 350 without addressing those "other" things is a recipe for disappointment.

THe exhaust system is one of them. Putting a loud obnoxious muffler such as a Blowmaster or the like, isn't going to make any material difference, however; the muffler isn't the restriction.

THere's no reason NOT to mod a 305 IMO, as long as you DON'T TOUCH THE SHORT BLOCK. Anything else - heads, cam, exhaust, gears, converter, and lots of other things - can be re-used on ANY motor if chosen wisely. Not so the short block: when it wears out or total disappointment sets in, you have to START OVER COMPLETELY FROM SCRATCH on a bigger motor, and put EVERY PENNY YOU WASTED ON THE 305 in the trash. Therefore avoid that.

Whole exhaust is a good idea. The operative concept being, WHOLE. Which means, don't even bother worrying about the muffler. Get yourself a set of chassis-specific headers, the highest quality you can afford; a new cat (they're only about $100); and a COMPLETE cat-back of your choice, in a larger size. Get stuff that's spec'ed for a 350, and that way it will work fine on your 305 but will be ready for the upgrade on down the road as well.

Next, consider a torque converter, and a set of gears.

Leave the motor itself ALONE if it works. Until those other things are addressed, "the engine" isn't what's MOST making the car slow. Attack the things that ARE making it slow instead.

 

im struggling with the same concept as well. my 305 tpi needs a valve job theirs a lot of blue smoke at start up. im on a budget considering im 18, i plan on taking it to the track next summer, theirs a guy by me on craigslist selling a rebuilt 355 for 500$ i want it so friggin bad but the engine is the least of my worries right now.

 

Blue smoke on startup doesn't necessarily mean you need a valve job. Most likely, it's just the valve seals that are shot. I'd also stay away from a "rebuilt 350" unless you know who rebuilt it and with what parts. A rebuilt 350 with stock smog heads isn't exactly a prize, and a "rebuilt" 350 whose rebuild consists of a fresh can of paint and 50 weight oil to cut down on the smoking is even less desirable. Unless he's got receipts showing that an engine shop did the whole rebuild, or at least a pile of summit receipts showing the parts he used, I'd be cautious.

 

That being so, perhaps a few mods to the 305 will be enough for you. (The question is whether, in the end, you'll be satisfied.) I went the 305 route long ago, as you can see below.

L69 dual snorkel with ducts/scoops
L69 exhaust manifolds, Y- and intermediate pipe--along with a high-flow cat
CK or DR secondary metering rods and B hanger
Air-valve tension tweak
Edelbrock intake
Summit cam
advanced timing

The car ran much better than its original 155 hp, but after swapping in a 350 HO Deluxe, I learned that the LG4 effort, while a valuable learning experience, was somewhat a waste of energy/money. Why? Ultimately, I and most hobbyists, I think, simply want more, more and finally more.

JamesC

 

Maybe I'm misreading here, but an '87 305 TPI won't have nearly as bad of an exhaust system as the LG4 would. But, good headers would still be better than the factory exhaust manifolds and Y-pipe. Cheap headers would not be so good. Look at Hooker 2055HKR - expensive, but they would bolt into your exhaust system, and would also be fine for a 350 down the road.

I also doubt an L69 air cleaner would fit on an LB9...

An aftermarket roller lifter cam would also help wake it up.

Beyond that, look into a 350.

 

I had an '87 Iroc with the 305 non TPI it was still carb and fun although not as fast, if I had kept it I would have modified the original 305 not because I didn't wanna go fast because I could have always swapped out the 305 for a 350 and take off like a rocket but mostly because I wanted to keep the original engine and have the car in original status exterior wise and interior wise with very minor non extreme mods under the hood just your basic bolt ons like Flowmaster 80's series exhaust, k&n filters, NGK sparkplugs, shift kit for the trans, new hi performance water pump / oil pump and 160 degree thermostat.

 

But if I had really wanted to go all in on the 305 to extract MAX POWER I would have done Cam Lifters, Heads & gears & since I had the Carbed LG4 I could also have put in a new Holley street avenger carb and really had a nice runner but that money would be better spent on the 350 because then you get even more power than in the 305

 

Not in Los Angeles.

 

What do you mean ?

 

He means, not in LA.

The CA inspection requirements will INSTANTLY eliminate ANY carb except a E4ME Q-Jet from consideration.

 

Hmmm....I've seen some 2nd and 3rd gens and a couple trucks running a holley carb here and their newer than '75.

 

Yeah sure; for a little less than 2 years at a time.

And, there are a few Holley carbs with a CARB EO #, for non-computer-controlled applications; 9895 for example.

Can you tell maybe, I've lived there before? Got some BTDTGTTS even?

 

I never saw so many different beliefs. Dropping a 350 in place of an LG4, even with none of the possible bolt-ons, still feels better than anything short of nitrous. Above 4500 RPM, it might be disappointing, but even when I had a really built 355 with a 3.73:1 axle, I still didn't get above 4000 more than 3 times in a typical week. Mod the 305 first if you like, but there's no guarantee of worse MPG with the 350. It won't downshift as much, and that can really help MPG. If you have a 2.73:1 axle, changing that would be the best place to start. 3.08:1 if you need MPG, 3.42:1 for more fun. Second mod should be an '87-up 350 short-block assembly with non-swirl 305 heads.