Looking for advice on engine swap

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HeavyD

n00b
Apr 27, 2015
2
0
1
I have an 85 Monte Carlo SS that recently started having compression problems. I'm going to rebuild or replace the engine. I just don't know which would be better. I can turn a wrench so pulling an engine from a salvage yard would be no problem. The motor that is in the car is a carbureted 350. I have a budget of 4k so there's not much to work with but I will pull the engine myself as well as installing the new one. Eventually I want to run turbos on the engine so forged components would be ideal. I have looked into crate engines but all of them within my budget have cast cranks and pistons. My problem is I don't know if I should choose a different engine to build or if I should just use the block I already have. Any help would be greatly appreciated.
 

Flyers9928

G-Body Guru
Jul 30, 2014
597
1,515
93
South Central Pa
Tear it down and send it to the machine shop, have them check it out. Tell them of your budget and plans and see what they think.
 
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MonteMan79

Not-quite-so-new-guy
Nov 6, 2010
11
1
3
Take this with a grain of salt because I haven't done it, only researched.

If you want to run turbos, I would suggest a craigslist 5.3 or 6.0 LS motor. with a 4K budget, you should be able to find a nice one with all harnesses for ~1K, plus 3K to get it in the car and running. Depending on how far you want push it, you wouldnt have to tear it apart to add turbo(s) later either.
 

gbodytoys

G-Body Guru
May 1, 2014
501
646
93
Detroit, MI
if you were satisfied with your motor prior to the compression issues, it would be worth having it checked out.

If you weren't, 4k goes a long way in my opinion, regardless if you build it, get one from craigslist, or buy a crate that is ready to go with no alterations. 383's, 400's, and of course 350's can be had oil pan to carb (or atleast intake) for less than 4k.

How much hp/torque are you looking for?
 

Yav8

Master Mechanic
Aug 19, 2014
275
114
43
Manitowoc wis.
Did a budget build on the 81 Olds. Started with a 5.7 vortec long block so I had the heads rollers spiders dog bones windage tray and all the tin to complete the motor. Had the motor cleaned and honed with new cam bearings installed. I when ordered a Eagle 383 stroker kit in STANDARD bore 9.5-1 pistons because the vortec have very little ware on the cylinders. Cam choice was a ebay buy from a place that regrinds roller cams. I chose the smallest one which is a copy of the Comp. EX-270. Heads are the vortecs with some home porting and a upgrade to Z-28 valve springs. Price list is $100 for the core, $60 to have the block cleaned honed and cam bearing installed. Stroker kit was $800 off ebay and the cam was $140 and shipping. $1200 total with me doing most of the work on the motor, I for got a used intake and a 750 carb and HEI. Trans is a th350 shift kit 3.42 gears out back and a 1800-2200 stall converter. Last weekend out with good spring air it went 12.52 at 109MPH shifting at 5600rpms. If any body want more information PM me and we can talk.
 

theoldsone

G-Body Guru
Dec 26, 2014
799
246
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Building a turbo anything asnt easy. But who doesnt like a challange. My sugestion would be stick with cast iron heads. Im assuming your engine is a 350 and doesnt have a forged crank. If your lucky enough to have a junk yard near you id tell you to look for a truck 350. Its more common to find Truck 350's with 4 bolt mains and a forged crank, and rods not those powdered ones. IDk powdered rods arent as strong IMO. You'd also want to find at a low comp head. At best a 993 or a 991. 991's have smaller valves though. And 993's are casted thicker and have larger valves than a 991. Maybe thicker than most stock 350 heads. These two are 76cc heads. With dished pistons you'd be looking a 8:1 ish but id suggest flat top pistons you'd be closer to 9:1 and have a better quench area perfect for keeping those cylinders cooler.finding this combination of parts barley costs $300 if your lucky. Keep milling to a minimum you like low comp with turbos. Dont buy a crate engine if you want specific specs for a turbo 350. Your going to have to dig up tons of info. Trust me knowledge is power and with knowledge you can save big $$$.
 

Yav8

Master Mechanic
Aug 19, 2014
275
114
43
Manitowoc wis.
You will be looking for a very long time to find a 4 bolt main block with a forged crank in the junk yards. As for the PM rods they are the upgrade to the factory pink rods. People have been boosting, blowing and spraying these motors for a long time with these stock PM rods. These rods were used in some of the vortec and all of the LT1 later motors and on up to the present. If you want you can always order a complete kit from some one like Comp Products and have the bore size you need, upgraded rods and forged crank and pistons just the way you want with out the piece meal of junk yard parts trying to get something on the cheap. As for heads most of the smog heads came with 1.94 and 1.5 valves, and any of these can be upgraded to the 2.02/1.6 valves and all the 350 motors came with close to 74cc combustion chambers.
 

lilbowtie

Comic Book Super Hero
Jan 7, 2006
3,460
3,965
113
Canton Mi
Only you can weight your options, seeing you want to build a turbo engine I would try to make due with what you have - either drive it as is or it might just need a valve job. Do you realize how much it will cost to build a good turbo engine and upgrade your drive train and is this in your near future? You really don't know what you are getting with most bone yard engines and if you can wrench there is a lot of 350 stuff out there you can build one. Don't know where you are located but I have several virgin 350 4 bolts and a couple of steel cranks. Even have a 5.3
 
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HeavyD

n00b
Apr 27, 2015
2
0
1
I just want to get prepared for turbos. It will be a while before I get the money to get a proper turbo setup. In the meantime I figured I could build an engine that will withstand it. As the car sits it has so much blowby the dipstick won't even stay in place. I parked it and pulled the intake and heads off for further inspection. I couldn't see any significant damage or wear but I don't know much. I still have ALOT to learn. There was a significant amount of carbon buildup on the pistons. I have upgraded the rear end to a detroit locker with 3.73 gears. Transmission is just a TH350 so that will have to be upgraded eventually but for now I just want to focus on the engine. I'll probably just end up taking the engine to a highly recommended machine shop down the road and seeing what they have to say about it. I have considered a 5.3 or just stroking my 350 to a 383. Even thought I might get a little ridiculous and put a 454 in it. I have several salvage yards within my area so finding an engine is no problem. I just honestly don't know what is the best way to go. It is my daily driver but I do a bit of street racing so obviously the more power the better. There is definitely alot to think about. I greatly appreciate all of you for commenting and welcome more opinions
 
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