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1988 350 rebuild

R

riv1973

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Hi All!

my son and i have a 1988 Chevy K5 blazer and we are going to work on the 350. we wanted to do some performance upgrades. the engine smokes a little on start up. i think this is worn vavle seats causing oil to drip down onto the pistons while it is not running and then burn off at start up. it does not burn oil while running.

was thinking of a few upgrades we can do. was wondering about upgrading the heads and any changes we can make to this motor to increase performance and freshen it up.

was also thinking of getting a 350 from our local junkyard out of a 1987 blazer and rebuilding it completely.

the motor we have in the truck has been replaced and has unknown miles on it. i think it came from a junk yard before it went into our truck ( under prior ownership).

looking for some advice on where to go. would like to do a cool project with my son to show him what building a motor is like. so ia am leaning towards building a junkyard motor up. the benefit of this is that the truck will be driveable during this process. you know how machine shops can get delayed.

also any thoughts on upgrades to a 350 we can do to make it slightly more powerful ( VORTEC stuff, edelbrock heads, cam change)? nothing crazy as we want to keep the TBI system.

thanks

john
 
Since this is a first project for the two of you I’d keep it simple so that it goes back together smoothly and you can have it running quickly. Do a stock rebuild, add a vortec fuel pump and have the injectors cleaned and flow tested. This will let you all enjoy the Blazer without chasing down issues with cam swaps, header leaks, and trying to get chips burned or programming them yourself. A custom burned chip now is over $400.

You won’t notice a big performance difference but reliability will be there and he can drive the snot out of it and chase ladies. My 2 cents.
 
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very good idea! this is mostly for the process and not making this a speed demon. we want to learn. we are looking at an engine we can get out of a yard today that we can rebuild so the truck can stay running through all this. it is from a 1987 blazer. and is a 350.

john
 
That 350 is great to learn on and parts are the most affordable. It will be fun and a success right off.
 
You might want to visit Chevrolets performance catalog and get an idea what a modern factory equivalent or better engine costs.

When you cost out acid dipping(wash) the block before & after , boring said block , new pistons , roller cam & lifters, roller rockers, gear drive cam assembly, regrinding or a new forged steel crankshaft, balancing the rotating assembly.....

The 202 heads are getting hard to find ....
Most of this " project" is machine shop time, I'm hard pressed to see the quality or learning experience?

The last one I touched was 30 years ago & I sent it out rather than learn how to use my engine boring bar. We own boring equipment, head valve grinding equipment , mills + lathes....

That job wasn't worth the costs of doing it.... Sent it out to the Retired owner of small engine machine shop.... Yes , I got a friend ,/ family discount and was very happy with the end result. The parts prices can be very lofty......their were no hi performance factory engine packages, or I would have considered it.
 
For your junk yard engine look for a one piece rear main seal and roller cam block. We are assuming your k5 is TBI fuel injected ? If so you need to stay close to factory cam specs, but a small compression bump will be beneficial performance wise. As you get ready to order parts check in here 1st. while you may get some different opinions, not as many as FB, we do have a few professional engine builders, and couple of suppliers as active members.
 
Summit lists the LO5 at $4700.

No idea what machining costs, but GM cranked their crate engine prices WAAAY up a couple years back. Haven't priced out components for awhile, but I would think a machine shop could do it (plus parts) for less.

Still have to be careful to avoid the "oh lets do this and lets do that" with these TBI setups. As mentioned, you can do very little to them before you need to start having chips burned.

While I like roller camshafts in this day and age, even finding one of those that will play nice with stock TBI tuning is probably unrealistic.
 
Isn’t TBI already a roller cam? I’d rebuild the heads (valve guides and seals) and drive the thing
 
Not in the pickups or SUVs, the 89 and up blocks are drilled for a roller and some 87’s are as well. Its still a $700+ deal to put in a roller cam and the gains aren’t great without a bucket of money to change the heads, and have the TBI worked and tuned.
 
For me the shortblock would be relatively stock but balanced and 4 valve relief flattop pistons. Cam I would talk with a cam manufacturer and go with a roller spec'd to work with your TBI without having to get a chip burned. Heads a set of Dart Iron Eagle S/S heads with 76cc chambers and 165cc intake runners, good for roughly 9.0:1ish compression topped with an Edelbrock TBI manifold. This should get you a stout running engine.
 
Just need to be careful with flow and lift.

TBI cannot adjust for fueling requirements under heavy throttle. At cruise the O2 sensor can help fueling, but it does nothing under load...which is where a lean condition will manifest if flow through the engine is improved. It's really hard to know how it's really running unless you are datalogging and can watch knock and see what the fuel trim is at cruise.

At best you can leave performance on the table, at worst you can make performance worse by running into knock under load. A couple degrees of lost timing due to knock under heavy load, makes a world of difference.
 
eodcoduto said:
Not in the pickups or SUVs, the 89 and up blocks are drilled for a roller and some 87’s are as well. Its still a $700+ deal to put in a roller cam and the gains aren’t great without a bucket of money to change the heads, and have the TBI worked and tuned.
Click to expand...
My reasoning for a roller would be the modern oils lacking the zinc to keep a flat tappet alive. Cams and lifters nowadays are junk, no way would I do a flat tappet anymore
 
It depends on what you are doing for sure. I’ve done a couple of stock engines in the last year and haven’t had any problems but the lifter issue is real. Getting ones that are properly ground is the key. Does anyone have a cheap source for vortec lifters and plates?
 
riv1973 said:
Hi All!

my son and i have a 1988 Chevy K5 blazer and we are going to work on the 350. we wanted to do some performance upgrades. the engine smokes a little on start up. i think this is worn vavle seats causing oil to drip down onto the pistons while it is not running and then burn off at start up. it does not burn oil while running.

was thinking of a few upgrades we can do. was wondering about upgrading the heads and any changes we can make to this motor to increase performance and freshen it up.

was also thinking of getting a 350 from our local junkyard out of a 1987 blazer and rebuilding it completely.

the motor we have in the truck has been replaced and has unknown miles on it. i think it came from a junk yard before it went into our truck ( under prior ownership).

looking for some advice on where to go. would like to do a cool project with my son to show him what building a motor is like. so ia am leaning towards building a junkyard motor up. the benefit of this is that the truck will be driveable during this process. you know how machine shops can get delayed.

also any thoughts on upgrades to a 350 we can do to make it slightly more powerful ( VORTEC stuff, edelbrock heads, cam change)? nothing crazy as we want to keep the TBI system.

thanks

john
Click to expand...
Im not a motor builder or expert by any means, but i did close to what you're talking about a couple years ago.. i built a tbi 350 with flat top pistons and a mild comp cam.. had some 906 vortec heads rebuilt and a gm performance manifold... im super happy with my motor but the juice isnt worth the squeeze.. had to have a chip cut which was pricey as was the intake manifold.... and i upgraded the fuel pump.. i run long tube headers with the 02 bung in a little extension piece.. it was my first time building a motor so i learned a whole lot and i had fun doing it, but it was very expensive for a slightly better than stock setup... plus like others have mentioned, i built all hydraulic flat tappet stuff which requires special oil... if i could do it again, id just go back completely stock, or build a bitchin high-performance motor with a stand alone fuel injection system... but... if you have any questions feel free to shoot them my way
 
Find a junkyard car engine, and you can get all of the roller cam parts. Even an LO3 out of a Camaro. The 305 stuff works in a 350. You could just run an LO5 roller cam from a Caprice. Definitely do a roller cam.

Martin
 
I'm with @Wes Harden . Find a factory roller block, clean it up and lightly refresh it. Toss on a set of decent small chamber or vortec heads and enjoy the time with your son. A factory LT1 cam will help give you a bump in torque and make a really nice foundation. Plenty of help here if you need it. We've all been there or still are.
 
When anybody askes about rebuilding a TBI engine I always say...the heads are no good for rebuilding on TBI engines. TBI heads are very prone to cracking from old age, and are not good candidates for rebuilding. TBI blocks are great for rebuilding, just not the heads.
 
hey all! thanks for all the feed back. so i am now leaning towards a stock rebuild but the roller cam ( keeping the specs close to stock) and the VORTEC heads with a rebuilt TBI unit ( i bet ours needs a freshening up. we get some surging at idle now) is the way we should go. we could get a 350 out of a Blazer here for cheap money and then rebuild it but i see GM has a stock 210 hp replacement engine available as a long block. i was wondering if we could get a short block of that engine and get VORTEC heads new along with a roller cam with stock specs. out motor is tired. it still runs but leaks coolant from somewhere and is just tired. if i get a donor block i can have the work done on it while the truck is still driveable. but a GM short block with new parts ( heads and cam as i stated above) would be ideal i wuold think. this would not require a new chip or computer work correct?
 
riv1973 said:
hey all! thanks for all the feed back. so i am now leaning towards a stock rebuild but the roller cam ( keeping the specs close to stock) and the VORTEC heads with a rebuilt TBI unit ( i bet ours needs a freshening up. we get some surging at idle now) is the way we should go. we could get a 350 out of a Blazer here for cheap money and then rebuild it but i see GM has a stock 210 hp replacement engine available as a long block. i was wondering if we could get a short block of that engine and get VORTEC heads new along with a roller cam with stock specs. out motor is tired. it still runs but leaks coolant from somewhere and is just tired. if i get a donor block i can have the work done on it while the truck is still driveable. but a GM short block with new parts ( heads and cam as i stated above) would be ideal i wuold think. this would not require a new chip or computer work correct?
Click to expand...
You could get a complete L31 crate engine for $5000.
 
I have a full LQ 4 from fan to MAS airflow set up, pedals, all the computers and the whole thing including the 4L60E trans in my garage with only 100,000 on it. I would like to swap thst in now that I am looking at the cost of even a LO5. The LO5 is $4600 (best price I have found) long block shipped to my door. I figure another $500-$1000 for other parts.

How
Much more is a LQ4 swap? I got the motor as I described plus trans and transfer case (obviously not using) for $1000.

So I figure getting the computers redone and using the stock LS harness, redoing the exhaust manifolds, new stock injectors, other new parts (water pump, new gaskets, and adapters for pullies and AC) can’t be more than $3000.

Also I found what I think is a remanufactured LO5 for half the GM cost. Anyone know this company? See picture below.

IMG_9666.png

IMG_9667.png
 
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