Got some questions. Need to replace the 305 tbi engine in my son's 91 RS. It it was a 700r4 car I really wouldn't mind putting a 350 in it, however, I don't have faith in the BW 5 speed behind a 350 with my son's foot on the gas pedal. He wan't more than a 305 so at this point we've agreed to build a 327. We've got a four bolt main 350 for the base. We'll get a 327 lg. journal crank, new rod (6" at least) and new pistions. We'll stay with a roller cam (ZZ4 most likely as they are available at a decent price on e-bay.) and most likely roller rockers as well. I'd like to stay around 9.5 to 10.0 compression ratio and keep all the computer, fuel injection system, sensors, etc.

We'd like to put a set of Vortec heads on it but I'm not sure what type of intake manifold to get to bolt up to the Vortec heads that can still use the tbi unit. Anyone else put a set of Vortec heads on a tbi car? Will the Vortec truck manifolds and throttle bodies work under the Camaro hood?

PS. It may be a false assumption but I believe the shorter stroke (less torque) 327 will be easier on the BW 5 speed than a 350.

 

I have witnessed a BW 5 speed get shreded by an almost stock 4.3 V6. If you power shift it alot, it WILL die, maybe not for a while, but it will. Now TQ does not kill it, as long as you are not power shifting it. I have seen them last for a long time behind even 406s as long as the driver fully released the clutch, before stomping back on the gas.

 

What I've read on this site is that GM never put them behind the 350's in Corvette's or Camaros and they didn't even put them behind TPI 305's till the "world class" version of the transmission became available. Anyway, my son wanted a 350 until I told him we'd build a 350 for it, and when he tore up the transmission the car got parked, license and insurance dropped and I got the 350 for one of my cars. We settled on the 327. He might still tear the transmission up (hey, it ain't a muncie) but we felt the torque reduction (GMs reason for not using the transmission on 350 cubic inch engines) would make it easier on the transmission. Anyway, we both like things that are "different" than the rest of the crowd so a 327 might be a good choice.

I realize some folks can tear up a rock.

 

Why not find a L99 carprice 265 baby LT1. Rob the 3" crank and 5.94" rods and put them in a 1 piece rear seal 350 block. Instant 302!

 

I never thought of that. I have one piece rear seal 350 block in the building out of an iroc. Thanks for the idea.

 

ON SALE: Check Out Our Specials Today 1994 - 1995 Caprice 4.3 V8 (L99) New Goodwrench Engine 88894191 - Crate Engine Depot

IMO, it would be worth it just for the 3" 1 piece seal crank and 5.94" PM rods. Then sell the rest on ebay. Hell, it might be worth it just to swap cams, add headers, port the heads, maybe mill them a little for more compression, deck the block?, LT1 carb conversion intake, TBI-carb adapter and go from there. Stock output is 200 FWHP/245 Ft/lbs. With the short 3" stroke it would be a screamer. You could easily get 250-275 HP 300 ft/lbs out of it. That would give you more performance than the stock 305 and not kill the T-5 as fast.

Rebuilding the Chevrolet LT1 Engine, Doug Anderson, Automotive Rebuilder, September 1999

 

Still in the "planning stages". Got the 350 block (4 bolt mains) stripped down Saturday. Need to find a machine shop to take it to to get it checked out. I don't expect too many problems. The old Laguna was still running great when I made the mistake of parking it 11 years ago. It ate the #8 plug at intervals of 3 to days to 3 weeks (must have been intake valve seals because the cylinder walls were bright and shiny) but I didn't mind it at the time. Anyway, I've ordered a ZZ4 cam off ebay, already have the high volume oil pump, too. After spending hours looking around on ebay and in general internet searches I found 327 crankshafts right down the road from me. Any NAPA or Autozone advertises they can get 327 cranks. Some of the numbers they list show to be forged cranks but I don't know if I'll have a choice. Prices are between $160 and $240. Don't know about the journal sizes yet. I've been told 10 - 10 undersized should be okay if they have them at that size or at standard. I'd like to put a set of 6" rods in it and get pistons with around 9.5 to 10.0 compression ratio. I'm also looking a set of new VORTEC heads. Between the VORTEC heads, the computerized TBI set up and premium gas we should be able to get away with a little more compression than the TPI setups (I hope). At this point I don't really see a need for windage trays or studs vs. bolts for the bearing caps and heads. We're also looking at a VORTEC air gap manifold with a tbi adaptor plate for mounting the TB.

Any advice, opinions, help will be read, thought about and used it helps.
Thanks.

PS. Just as a wonder (to me anyway) the 350 in my Laguna has not been started since the summer of 1995. There was no rust in the cast iron intake, the rocker arms were still oily, the lifter valley was as clean as an engine just being built (took pictures of that), the cylinder walls of 7 of the eight cylinders were still shiny and the pistons drove right out (it looked like a slight head gasket leak in the bottom corner of #7 had gone on for awhile as #7 had a puddle of rust in the bottom between the cylinder wall and the piston top - but it drove out after squirting WD40 on it). All the pushrods, rocker arms, rings, bearings, etc. were shiny once we wiped the oil off them. At this point I don't remember whether the last oil change was Valvoline 10W-40 or Castrol 10W-40 as I was using them interchangeably at that time.

 

What are the pros/cons of mechanical roller lifters vs. hydraulic roller lifters?

So far we've got:
1. 327 large journal crankshaft/main/rod bearings on order
2. ZZ4 cam
3. air gap vortec manifold
4. vortec heads (2.02 intake valves and 1.60 exhaust w/.550 lift springs) on order
5. melling hi-volume oil pump/pickup/steel drive shaft/pick up retainer
6. we'll be re-using the original 350 4 bolt block, oil pan, timing cover, center bolt valve covers (off the 305), the headers off the 305
7. 6" SCAT connecting rods on order
8. still need to get pistons (once we know what diameter to order)
9. still need to get lifters, push rods and rocker arms
10. have most of the gaskets/seals
11. need a "cam button" for the cam
12. need a timing chain/gears
13. anyone have an idea of whether the 305 knock sensor or a 350 knock sensor would be best.
14. Oh, we're planning on a TBI to intake adaptor to mount the TBI to the vortec air gap manifold
probably a long list of small stuff that will add up as we go along

 

Don't forget about tuning stuff. The setup sounds good. You could always get a th350 for the tranny.

 

a friend of mine had an 89 2.8 5-speed that blew from hard driving over the course of 3 years, you're talkin about 160 pounds of torque here, he never touched the engine, he just drove it hard.

also, he knows how to drive a manual, never was there the smell of burning clutch or anything, and when they tore it apart, 1st and 2nd gear were the only ones really eaten up (other than the fact that the reverse gear quite literally blew out the side of the tranny, leaving a golf ball sized hole in it), but the point is that they're just not especially strong tranny's stock, no matter what you put 'em on.

why not look into a tremec? they can be had for really quite cheap as far as transmissions go, I've heard of a guy who switched his 4th gen auto to a manual tremec t-56 for 1300 bucks. i'm not sure how extensive the difference would be for you, but I'd say that a price anywhere near that is worth it for the security of knowing you're not going to blow that transmission do to inherent building flaws. also, i belive tremec t-5's are cheaper, and htat would make the swap almost painless for you if the car already has a t-5, which sounds like the case.

I dunno, i'm just throwing it out there.

as for the engine, sweet.

 

GM Performance Parts makes a TBI intake to fit the vortec heads. It is a little pricey but can sometimes be found on ebay fairly reasonable. that is what i did. if you plan on keeping stock hood, check the heights of what you end up with. the air gap and adapter may have you too high for stock hood. i had to remove the spacer from under the air cleaner, use a flat base and only a 2 1/2 inch filter to stay under my firebird hood. you will not be able to retain EGR function unless you pipe it externally.

 

Well, finally got it in the car and runnning (just idling and a few excursions to 2 and 3 thousand rpm). So far no check engine lights when idling even long enough to go through several cooling fan on/cooling fan off cycles. Had a bad head that leaked (poured) water all down in the head. Leaked so bad we couldn't figure out why the radiator level was dropping so quick (after filling it with water 2X) and then we heard the water dripping out of the header and converter flanges. Had to quickly drop the headers, pull the distributor, TB and intake and pull the passenger side head and dry out the #3 and 5 cylinders which had filled with water. Got another head and put on it and no more issues.

Got the nose back on it today. Still need to get a hole cut in the hood and a hood scoop installed as the new edelbrock airgap manifold makes the TB sit up too high for the air filter housing to clear the hood now. Will also pull all the stuff in the way of removing the valve covers and recheck the lash on the valves one more time before letting him run it up and down the road in front of the house and making an appointment for an inspection.

Had to make a new vacuum connection arrangement for the power brakes as the air gap fitting on the #7 cylinder runner was about 1/8" below the fuel line on the passenger rear side of the TB. This has been a project loaded from beginning to end with uh ohs and aw $hits that cost time and money to compensate for stuff we thought would fit but didn't.

1 - ordered all the valve train parts (cam, lifters, push rods and rocker arms from the same place but the push rods were too short, after getting an on the phone run around I bought a push rod length checker and new pushrods from a different place
2 - already mentioned the problem with the one head, that's not resolved yet but the place has a one year warranty on the new heads and they are asking me to "recheck" the leak to make sure its not the head. I'm sure not going to bolt it back on the engine and try it but I'll get around to trying it on a piece of sheet metal or plexiglass
3 - also the initial cam button was too long so we had to order a shorter one to get the timing chain cover to bolt on
4 - the kid's 20, so I know he's gonna "exercise" his new engine so I bought a heavy duty clutch, pressure plate and flywheel, well, the heavy duty stuff won't clear the factory bell housing so we had to order a steel racing bell housing to clear the new stuff
5 - the stock starter wouldn't work with the new bell housing so we had to buy one of those gear reduction starters
6 - took a little bit of fiddlin' to get the timing chain cover and oil pan and gasket to seal up front, the new GM authorized timing cover was way to short to seal up with the oil pan (you could stick a screw driver between them)
7 - we broke the speed sensor when we forgot to disconnect it before dropping the transmission so we could get the engine back in and looked around awhile trying to find one before we bought a new one
8 - the new polyurethane motor mount inserts had some little "ears" sticking out of all four corners that wouldn't clear the dang "covers" that bolt to the engine so we had to grind the top ears off them to get the engine down on the mounts
9 - the "kid" won't take my advice about bagging and tagging his nuts, bolts, small parts, etc. and putting them away so just about every attempt to work on the thing results in lots of wasted time trying to find those nuts, bolts, sensors, etc. (this has resulted in my promise for no more car projects with him till he grows up and figures out I do have good ideas some times)
10 - the engine sits up a little higher with the new motor mounts so we had to modify the nice cover he made for his heater/fan last year when he took all the AC stuff off the car
11 - the lakewood rubber boot that should seal between the lakewood belhousing and the clutch arm doesn't come close to fitting the hole in the bellhousing so it had to be measured/trimmed/measured/trimmed/trial fit/trimmed/glued into place which required the slave cylinder to be unbolted a couple of times before it fit as good as we could make it fit
12 - spent a lot of time playing with that adjustable pivot ball on the new bellhousing trying to get complete clutch release with no luck. Ended up making a slightly longer rod to fit between the slave cylinder and the clutch fork arm
13 - probably some more I can't think of right now, man this has been a pain in the behind

for some reason the winaldl won't function with his car. Haven't tried it on my TPI IROC lately but I used to "record" data when hooked up to it. We need to figure out why it won't work with his car and do some "mapping" of the data to see if it is running okay.

Now, to start getting ready for my engine build - a 335" stroker TPI for my other 86 IROC. I know, everyone says build a 350 or 383 but the stock 305 in my black IROC runs good enough to scare the shot out of me and most people that want to pester me on the road - just ask that guy in the twin turbo Mitsubishi or the Porshe boxter convertible (I wonder if called his salesman up and bitched him out because he couldn't run away from that dirty black Camaro).

Thanks for the earlier advice. I'll post again once he's had it out a few times to either let you know it's running okay or we're having more problems, one or the other. We did get a set of 350 injectors for it but haven't put them in yet. He also cut off all those projections sticking up from the top of the TB and radiused and polished the bores at the top to smooth out airflow entering the bores).

 

Well, now it still starts and idles fine but it's backfiring up through the TB when you pop the gas pedal down. He can't find the paperwork on his cam/lifters but "thinks" the lash was supposed to be at 22 thousandths so we readjusted them the other day (they were at 16 thousandths) but it didn't make any difference it's still popping back through the throttle body.

It wasn't doing that when we first got it running so we're kind of at a loss about what to do about it. Any suggestions of what to check on would be appreciated. Thanks.

 

Got rid of the back fire by advancing the timing (out past the timing mark). That also reduced the hesitation but as we continued to advance the time we never completely got rid of the hesitation but did get to the point where even that gear reduction starter won't start the car.

350 injectors to go in the car after we get the timing back to just a little more advanced above the point where the backfire starts.

I sure would hate to throw in the towel and bolt a 4 barrel and a vacuum advance distributor on it but that's a last resort.

 

Did a little experiment yesterday. Not sure how it squares with anyone elses experience.

Unplugged the vacuum line to the MAP sensor. Plugged in a vacuum ga. to the port on the back of the TB and used one of those vacuum hand pumps to put different levels of vacuum to the sensor.

At normal idle the vac. ga. showed a steady 16". This was with the hand tool putting 15" of vacuum on the MAP sensor.

I'm not sure what the vacuum should be on a healthy TBI engine. I did notice that if I slowly increased the vacuum to the MAP to 16" the vac. ga. began to show unsteady manifold vacuum. If I took the MAP to 17" the engine got really rough and by 18" the engine just died - did this a couple of times. At this time I'm assuming the 16" at idle is due to the cam we used.

I remember my dad using a vac. ga. to set the timing on his GM trucks (292 big 6's) and he'd settle on about 18 or 19" at idle where the timing was right. We don't seem to be able to get that much on the TBI engine. Just for reference we went over to my IROC (305 TPI) and checked it and it read a solid smooth 20" at idle.

Did notice that the vac. tool was sucking some kind of thin brown liquid out of the MAP sensor. Probably moisture collected during the year that car set between removal of the old 305 and installation of the new 327. We'll see about getting a new MAP sensor in case the brown is "rust" and the MAP sensor may be affected.

 

Well, just to finish this up.

My son isn't going to invest the time/effort into learning to modify the TBI system program for the car.

He bought an Edelbrock 650 cfm AVS and a fuel pressure regulator and I gave him a news vacuum advance distributor I'd been holding for another project.

Made a few adjustments for the throttle cable, the air filter spacer, etc. and he's "flying high". So far he's getting 20 mpg driving around town. The engine seems to have good torque even at low rpm as he says it will run down the road at 55 mph while turning only 1300 rpm in 5th. Figure we'll change the oil at 1000 miles and use regular oil again (10W30 Castrol). The do a couple 3000 mile oil and filter changes and then switch over to synthetic oil.

Oh, did buy an Edelbrock O2 sensor/gauge to help with the tuning of the carb. and used it right off the bat to set the fuel mixture up front. He'll just have to drive it awhile to see if any jet changes need to be made.

He's HAPPY! Now, to get on with a project or two of mine.

Have a good one.