Engine build

[bucata206]

Hey guys. As I mentioned in my welcome post, I have a 79 K10 with a 350. I am trying to decide how to go about rebuilding the motor. Crate motor long block or just rebuild what I have. I do not have a whole lot of money so i am trying to do things as i go and really don't want to take the truck out of commission for a long period of time.

I am looking to build a motor with decent power and torque (I'm more concerned about the torque numbers than the horsepower numbers.) I would also like a good exhaust note. Of course I would love to have the nice low loping sound but I know that is not always attainable. What do you guys recommend as far as pistons/compression, cam, headers, carb and general bottom end and head work?

I apologize now for my ignorance on this topic... This is my first time ever working on a 350. This was going to be a project with my father (who knew all about 350s as he used to drag race them.) Since he passed in 06, I have no guidance from anyone on how to build this motor... Not giving a sob story, just giving an explaination of my lack of knowledge at this point in time.

 

[Boone83K10]

Hey welcome. No worries about ignorance. We all started out with no knowledge. If this is you daily driver then I say get a long block and start from there. If it is not your daily driver, then I say rebuild what you have.. and do it yourself. That is the best way to learn anything. The knowledge you gain from self trial and error is so much greater than being shown by someone or by having someone else do it.

Sorry about your dad.

 

[bucata206]

O this is definitely not a daily driver. Once it is built I would like to drive it more but it would mostly be a for fun truck

 

[bucata206]

Any one have any suggestions on pistons/compression ratio and a decent cam for a good sound and power numbers?

I would do it by trial and error but I don't have the money to support that unfortunately with everything else that needs to be done with the truck.

 

[Driver4r]

To run decent on today's fuel(80's octane) I would stay in the 9-9.5 range.

 

[shortboxchevy77]

O this is definitely not a daily driver. Once it is built I would like to drive it more but it would mostly be a for fun truck

Since you are more than likely running standard late 70's heads I'll give you a good combo that I have used many times over on many sbc's.

Flat top hypereutectic pistons and something along the lines of a 260 or 270 series comp cam. If you get on a website like jegs or summit comp will show a chart that tells you the power ranges that each cam is designed to perform in, this information will help you decide what you need based on what rpm range your truck is going to be normally operating in. Don't be cheap on the cam, buy a good name like comp. Cheap cams from elgin and summit can be problematic due to lack of quality control.

Have the block hot tanked and have the shop check the cylinder bores for you before you order pistons, depending on the shape of the bore you may be okay with a good honing or they may need to be bored .20 or .30 over. Have them install your new cam bearings while they have it. Take the crank in with the block so they can clean it, check the journals and polish or turn it. Most cranks coming out of a healthy engine usually just need polished.

Have your heads checked out, they will probably benefit from a full rebuild. If the valves and seats are in good shape they can be reused after a 3 angle grind and a new set of guides and seals. After you know what size of pistons and bearings you will need I suggest you buy from Northern Automotive. They offer complete engine kits at really good prices. The kits contain quality parts and you can personalize the order with whatever pistons and cam you like.

After you get it all back and start assembly of the engine cleanliness is next to godliness, this I cannot stress enough. Use a chiltons or Haynes manual to get your assembly torque specs and assembly procedures and follow them to a T. Be generous with assembly lube with your cam and coat your crank bearing evenly with it during assembly. Wipe your cylinders down with a clean cloth soaked in oil when installing your pistons, slip rubber hose over the rod bolts when installing the pistons so you do not knick your crank.

Sorry for the long post, just trying to cover all the bases for ya lol.

 

[bucata206]

Since you are more than likely running standard late 70's heads I'll give you a good combo that I have used many times over on many sbc's.

Flat top hypereutectic pistons and something along the lines of a 260 or 270 series comp cam. If you get on a website like jegs or summit comp will show a chart that tells you the power ranges that each cam is designed to perform in, this information will help you decide what you need based on what rpm range your truck is going to be normally operating in. Don't be cheap on the cam, buy a good name like comp. Cheap cams from elgin and summit can be problematic due to lack of quality control.

Have the block hot tanked and have the shop check the cylinder bores for you before you order pistons, depending on the shape of the bore you may be okay with a good honing or they may need to be bored .20 or .30 over. Have them install your new cam bearings while they have it. Take the crank in with the block so they can clean it, check the journals and polish or turn it. Most cranks coming out of a healthy engine usually just need polished.

Have your heads checked out, they will probably benefit from a full rebuild. If the valves and seats are in good shape they can be reused after a 3 angle grind and a new set of guides and seals. After you know what size of pistons and bearings you will need I suggest you buy from Northern Automotive. They offer complete engine kits at really good prices. The kits contain quality parts and you can personalize the order with whatever pistons and cam you like.

After you get it all back and start assembly of the engine cleanliness is next to godliness, this I cannot stress enough. Use a chiltons or Haynes manual to get your assembly torque specs and assembly procedures and follow them to a T. Be generous with assembly lube with your cam and coat your crank bearing evenly with it during assembly. Wipe your cylinders down with a clean cloth soaked in oil when installing your pistons, slip rubber hose over the rod bolts when installing the pistons so you do not knick your crank.

Sorry for the long post, just trying to cover all the bases for ya lol.

This is great! Thank you! Couple question (and as always i apologize for my ignorance) how do i find a 260 or 270 series cam? Is that the "advertised duration" on Summit?

Also I tried looking up northern automotive and all I found was what looks like a site for a local shop in Illinois

 

[shortboxchevy77]

Here is the link for Northern auto parts http://www.northernautoparts.com/ you can request a catalog and they will send you one for free. Here is a page with a good selection of cams for you from Jegs http://www.jegs.com/webapp/wcs/stor...&N=1542105+4294963872+3011881+3005730+3015214

You'll see the magnum 270 cam at the top and towards the bottom of the page to the right you will see an extreme 4x4 cam that has similar lift and duration to the 270. Look through them and they will tell you what rpm ranges they were designed to perform in along with what kind of idle characteristics you might expect from them. Hope this helps.

 

[bucata206]

Great thank you!

 

[bucata206]

Came across a 350 out of a 74 chevy. Just confirming that there is really no difference in the years until the motors changed to the LT series and LS series right??

 

[bucata206]

Also does anyone recommend any specific modifications (other than get a bigger motor) to produce more torque? Like I said before I'm more focused on torque numbers than horsepower numbers (though they pretty much go hand in hand.)

 

[shortboxchevy77]

Came across a 350 out of a 74 chevy. Just confirming that there is really no difference in the years until the motors changed to the LT series and LS series right??

The motor is mechanically Identical to the one you currently have, heads may be different (combustion chamber/valve size) depending on a number of variables but they are mechanically the same and will bolt up. If you really want more torque look into turning the 350 into a 383 stroker. Making a stroker involves a fair amount more work though such as clearancing the block for the stroker crank weights and whatnot.

A nice compliment to a regular old 350 would be to have your heads ported by a performance shop and then have a good aftermarket intake port matched to the heads.

 

[HotRodPC]

There a minor differences as in 2 pc and single pc rear main seals. Dipstick tubes on opposite sides of the motor etc. If that's important to you, make sure you know what you're getting. I believe it's 86 down is 2pc rear main, and 87 up is single piece IIRC.

 

[hirschdalechevy]

A 383 is were its at for torque , if you want to spend the extra dollar's. The secret is heads for power. After market is the way to go but costly. I have a 350 in a 78 that has 1970 202 heads (mildly ported) with acc. holes and a comp 270 magnum hyd. roller cam in it with flat top forged pistons at 0 deck (9.8 to 1 appx.) . 35" tire's with 4.11 gears and it hauls ass , (350 hp appx.). Vortec heads are a great set up as well. All the bolt on stuff helps , (headers , intake etc..) but real power comes from compression , heads , cam. A stock rv cammed motor can run strong with bolt ons but to get any real torque and hp you need to bring the compression up and have a good set of heads and a cam to match imo.

 

[HotRodPC]

A 383 is were its at for torque , if you want to spend the extra dollar's. The secret is heads for power. After market is the way to go but costly. I have a 350 in a 78 that has 1970 202 heads (mildly ported) with acc. holes and a comp 270 magnum hyd. roller cam in it with flat top forged pistons at 0 deck (9.8 to 1 appx.) . 35" tire's with 4.11 gears and it hauls ass , (350 hp appx.). Vortec heads are a great set up as well. All the bolt on stuff helps , (headers , intake etc..) but real power comes from compression , heads , cam. A stock rv cammed motor can run strong with bolt ons but to get any real torque and hp you need to bring the compression up and have a good set of heads and a cam to match imo.

All True !!! You can cam it, bolt on carbs, headers and all the goodies, but without some compression and some heads to make to make it breathe, then you're bolts ons are just pissin' in the wind and you're not taking advantage of the bolt ons due to the bottleneck.

And compression, you can punch someone 10x and they're still standing, unless you have some power behind the punch you're not going to get the knockdown. Consider compression the power behind the punch.