305 build advice. Any and all advice is appreciated!

[Ewhitaker0020]

My truck is an 84 Chevy K10 with the 305 engine.

I know,I know, it's just a wimpy 305 but I would like to do some bolt on improvements that will give the engine some more get up and go. But I know nothing about picking out a cam that will give me a performance increase, but without being too aggressive. What kind of lifters do I pair with that cam? Do I use my stock springs and rockers?

So far I've got some shorty headers, which I haven't installed yet. I have changed out the stock intake for an Edelbrock performer with an Edelbrock carb. Because it's a heavy truck, it's super slow in it's stock form. I'm just wanting to make it run better and be a little more fun to drive.

I'm needing advice on how to do this build in a budget friendly way. I don't know anybody personally who can help me with this. Any advice is appreciated.

 

[Octane]

You can go to a cam that gives it a lopey idle but too agressive a cam will require better valve springs.Your cam supplier can give you specifics.The 305 is stock 8.25.1 compression,the 350 is 8.50.1 compression.Not much difference but the 350 is still a bit stronger and most popular to build.Flowmasters and 2.5" dual exhausts help.If your engine came wth the factory 4 barrel it came with dished pistons.The combustion chambers on those heads are actually quite small but the dish pistons take away that much needed compression.What I would do is put a set of flat top pistons in it and it would surprise you the improvement that would make.Outside of that....free flowing exhaust and a good intake manifold and carb is about all you can do performance wise in my experience.I've built 350 engines

 

[bucket]

Find a pair of heads from an 80's Camaro with an L69 or LB9 305, then have them ported if the budget allows. Couple those with a mild cam, good intake and a set of long tube headers. That's probably about as cheap as you can hop up a 305. Anything beyond that and it starts costing big bucks... may as well go with a different engine at that point.

 

[Nonstop]

How tired is your engine, and what is your budget? Is it lifted or does it have bigger tires? Do you do a lot of freeway driving? I ask, because if you are looking to make it snappier or do a lot of in town driving, you may want to consider changing axles for some with lower gears. Axle sets can be purchased relatively cheap from a junkyard or Craigslist. Might save you from getting too deep into the engine and possibly snowballing.

Just a different approach.

 

[Ewhitaker0020]

How tired is your engine, and what is your budget? Is it lifted or does it have bigger tires? Do you do a lot of freeway driving? I ask, because if you are looking to make it snappier or do a lot of in town driving, you may want to consider changing axles for some with lower gears. Axle sets can be purchased relatively cheap from a junkyard or Craigslist. Might save you from getting too deep into the engine and possibly snowballing.

Just a different approach.

Really not sure how tired it is. It runs really well. Occasionally it will blow a smoke ring out the tail pipe, but does not smoke much other than that. Doesn't usually use oil, although I have a large oil leak in the back of the intake manifold because I did a bad job with the rtv when I installed it.

It has near stock tires 30's but I'm not sure how close that is to the original 235's. My budget is as cheap as I can be. But I can purchase parts one at a time until I have enough to fix up the engine. I do a fair amount of highway driving when I drive it because I like to drive it to work occasionally and when I do that's between 45 and 100 miles one way at an average of 60-65 mph.

I know my truck came with the 3.08 rear axle ratio but I don't know if that's high or low.

 

[Ewhitaker0020]

Find a pair of heads from an 80's Camaro with an L69 or LB9 305, then have them ported if the budget allows. Couple those with a mild cam, good intake and a set of long tube headers. That's probably about as cheap as you can hop up a 305. Anything beyond that and it starts costing big bucks... may as well go with a different engine at that point.

What exactly is a mild cam? I don't even know what a big cam would be. I know I can get one to make it sound lopey and I wouldn't mind it sounding just a little like that, but I don't like how it sounds when it's really lopey and I've heard that doesn't add any power, but I don't know for sure.

 

[Ewhitaker0020]

You can go to a cam that gives it a lopey idle but too agressive a cam will require better valve springs.Your cam supplier can give you specifics.The 305 is stock 8.25.1 compression,the 350 is 8.50.1 compression.Not much difference but the 350 is still a bit stronger and most popular to build.Flowmasters and 2.5" dual exhausts help.If your engine came wth the factory 4 barrel it came with dished pistons.The combustion chambers on those heads are actually quite small but the dish pistons take away that much needed compression.What I would do is put a set of flat top pistons in it and it would surprise you the improvement that would make.Outside of that....free flowing exhaust and a good intake manifold and carb is about all you can do performance wise in my experience.I've built 350 engines

The exhaust will definitely come when I do the headers. Somebody suggested some heads from a Camaro and get them ported. Would I still do the flat top pistons if I changed the heads?

 

[Nonstop]

Really not sure how tired it is. It runs really well. Occasionally it will blow a smoke ring out the tail pipe, but does not smoke much other than that. Doesn't usually use oil, although I have a large oil leak in the back of the intake manifold because I did a bad job with the rtv when I installed it.

It has near stock tires 30's but I'm not sure how close that is to the original 235's. My budget is as cheap as I can be. But I can purchase parts one at a time until I have enough to fix up the engine. I do a fair amount of highway driving when I drive it because I like to drive it to work occasionally and when I do that's between 45 and 100 miles one way at an average of 60-65 mph.

I know my truck came with the 3.08 rear axle ratio but I don't know if that's high or low.

So, at this rate, may I suggest a compression test? It sounds like the engine MAY be starting to get tired. Find out the condition of what you have. May be throwing good money after bad investing a lot of money in it if it is bad. Might want to consider just driving it as is and save your money to buy a goodwrench 350 - $1900 new with a warranty!

 

[75gmck25]

You can also get a GMPP L31 crate engine and have Vortec heads, roller cam, etc. I swear these engines were only about $2100 just a few months ago, but they now seem to be going for $2700. However, it has much more performance potential than the base Goodwrench 350.

Bruce

 

[82sbshortbed]

I was doing the same as you with my 305. I got a new intake, new carb, new dizzy and new cam and mid length headers.

Here's the intake I used ran me about $150. New intake bolts and spacer for a brand new Quadrajet level 2(tuned for intake and headers) from national carburetor.

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Carb and spacer installed

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Cam ran me another 150 with new lifters and install lube

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I'm sure someone can interpret the paper work that came with it better than I can.

I installed the intake, carb and dizzy but, found a BBC 454 I couldn't pass up and never put on cam or headers. I can tell you I noticed a big improvement with just swapping out the carb, intake and dizzy tho. So I'm pretty sure the cam and headers would have been more improvement if I had installed them.

Now I'm kinda stuck on what to do when I pull the motor. Do I pull the new parts and sell individual or try and sell the motor with the new parts on it? I do have the cam tho if your interested. Like I said one of the guys on here can tell you if it's one you'd want or not. I sure don't need it now and will probably sell it with the motor when I pull it.

 

[Octane]

The exhaust will definitely come when I do the headers. Somebody suggested some heads from a Camaro and get them ported. Would I still do the flat top pistons if I changed the heads?

You can go to flat tops.And you cant go to big on the cam on a low compression egine like that without actually losing a little performance.But with heads and flat tops you can use a cam thats more for power and not just for that lopey idle everyone likes to hear.But as it has been said...these days you can get a crate motor with respectable power for cheaper than you can rebuild your own engine for usually.a

 

[shiftpro]

Friends don't let friends rebuild 305s. You can throw all the parts at you want but nothing replaces... displacement.
They never should have put these engines in trucks.
At least Eric's truck is a 2x, but still not worth it imo.

Sorry I know it's not what you want to hear...

 

[Ewhitaker0020]

Friends don't let friends rebuild 305s. You can throw all the parts at you want but nothing replaces... displacement.
They never should have put these engines in trucks.
At least Eric's truck is a 2x, but still not worth it imo.

Sorry I know it's not what you want to hear...

Lmao! Who's Eric? I'm asking because my name is Eric, but I don't think you knew that. I just can't afford anything that expensive right now. I plan on finding a used 350 or bigger engine that I can put on an engine stand and just work on it over a years time, slowly saving up money to buy all the parts.

 

[shiftpro]

Lmao! Who's Eric? I'm asking because my name is Eric, but I don't think you knew that. I just can't afford anything that expensive right now. I plan on finding a used 350 or bigger engine that I can put on an engine stand and just work on it over a years time, slowly saving up money to buy all the parts.

Yes you are Eric. I know your name because I am so fricken awesome and also I can read it over there on the left <.
If you have some $ to throw at the 305, which will leave you disappointed, just run it as is and put that loose coin into your future 350.

 

[idahovette]

Yes you are Eric. I know your name because I am so fricken awesome and also I can read it over there on the left <.
If you have some $ to throw at the 305, which will leave you disappointed, just run it as is and put that loose coin into your future 350.

The "awesomeness" becomes you!!!