Hi Guys, I am about to buy a 3g 1978 monte landau with the 305 engine. This car has no any mods on it, Its stock, and the transmission has to be rebuilt.

These old engine are underpowered. 5.0L v8 engine with 160 hp ..


So what I want is to rebuild the engine with good inner components in order to boost the power to at least 250 hp.

I have beed reading that changing the camshaft, lifters, carburator, valves, rings, crankshaft and hi flow exhaust may do the job. I am not a mechanic but want to buy the pieces and then take it to a Mechanic in order to do the JOB.

As I am in south america buying a rebuilt engine form the US and forward it to my country will cost too much. so I want to buy the kits and pieces to have a local mechanic do the job. SO I need advice.

Is it posible to upgrade the 305 engine cheapily to bost some power and having a good gas milleage. I have drive a landau before and that things was extremely slow and weak, I wont race it but I want a enjoyable runing.

 

The 305 was a decent engine, but the 350 is much more reliable and has more horsepower. It's a pretty common practice to replace that 305 with a 350. GM made millions of them and parts are cheap and plentiful new or used, in the U.S. or South America. IMO, you would be wise to take this route.

 

Thanks a lot. I have been reading online and found that there are several 350 engines.

from the L65 with 145 hp to the L46 with 350 hp.

I found 2 gm 350 engines on sale, they look mmmmm..... used

MOTOR 350 CHEBROLET COMPLETO - Quito

Motor 350 para chevrolet 1980 - Quito

I guess I should do a rebuild to them too, so the question comes again. bein a 305 or a 350 engine.... Which pats should I Upgrade in order to have a enjoyable driving and good milleage.

Any advices about the transmission??

 

350 - Intake, carb, headers and dual exhaust are a great start. You can get into porting and polishing the heads and boring the cylinders if you want real power, but for simple power with daily driving in mind the first 3 are an excellent start. These motors are limitless (kinda lol) with what you can do to them for getting amazing power and performance and the aftermarket options are endless and generally what most people choose when replacing a 305 in their car as it is pretty much a direct swap and you gain power instantly without touching anything and then can build up from there.

305 - Intake, carb, headers and dual exhaust again are the perfect start. You don't want to invest too much money into the 305 as you can only get so far on a budget, and to be honest you will eventually want a 350 lol. If you are going to have to rebuild the tranny I would personally look for a used turbo 350 tranny before rebuilding the one you have, it will be cheaper and you can find them fairly easy as they used them in a lot of different vehicles, then down the road if you want more out of it you can put a shift kit in it

 

Nice, thanks, and with this pieces changed. Intake, carb, headers and dual exhaust on the 305 engine.... How much would the power increase, from 160hp to .... ????? I wont race it, just want a car capable of behave like a modern 2.0 engine car for a daily driving and reliable for traveling to the beach (12 hours continue driving)

Wich carb do you recomend??

 

The headers and exhaust are going to realistically add probably 15 - 17 hp without doing much else as it will allow the car to flow better. I probably wouldn't bother replacing the carb a long as you already have a 4 barrel carb, the rochester carb from factory should work fine if you are sticking with the 305. An intake will help everything also flow better through the engine and will give you a slight gain. Here is exactly what you can do to get your car up to over 240 hp


f you want to improve the performance of an 305, you do the following: Replace all of the exhaust with headers, y-pipe with 2-1/2" downpipes to 3" at the cat, 3" cat, and 3" cat back to 3" inlet muffler (single 3" outlet or 2 x 2-1/2" outlets is your choice). Replace the cam with something with a little duration and lift (the Crane 2050 worked well in mine). Replace the valve springs with something that can handle the lift of the cam. Upgrade the ignition coil and module with aftermarket pieces. Replace the single-snorkel air cleaner with a dual snorkel unit, either a factory type (Camaros), or fabricated one . If you want, further improvements can be obtained by having the heads reworked for 1.94" intake valves, and cleaning up the port bowl area (do a search for porting, you'll find out what is required). Pinning the rocker studs or having the heads machined for screw-in studs is a very good idea with an upgraded cam & springs. If you want, you can put an aftermarket performance intake on it such as the Weiand Action+ or GMPP q-jet intake manifold, but I am a big fan of the edelbrock intakes

 

What I did on my 85 SS 305:


New cam: Crane 2040
New heads: World Products S/R Torquers
New Intake: Edelbrock 3706
Headers: Edelbrock TES
New exhaust: Dynomax Turbo


Installed AC Delco Rapid Fire plugs and MSD 8.5mm Super Conductor wires. Car runs strong with a nice idle. Not lopey at all. I haven't taken it to a dyno, but based on the mods, I calculate over 300 hp


Though now, my car is old enough it doesn't need a smog check anymore, I want to replace the headers and exhaust with a true dual and eliminate the cat. That will make a big difference. I have kept the original carb and computer through it all, and will with the headers, I will just make some modifications to eliminate the cat.

 

replacing the cam would mean replacing lifters too rigth?? I cant find a crane cam for a 1978 305 engine. only from 81 and so on.....


Does anybody know where could I find the sunroof glass and sunroof weather strip??

 

Yes with a cam you should replace lifters and valve springs for maximum benefit.


Try rockauto.com, or eventually they will come up for sale on Ebay you just have to wait long enough lol

 

Here's a link for your sunroof seal


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