http://www.s10forum.com/forum/f107/the-holy-grail-of-4-3-info-131868/

 

that dosent really tell me much lol. alot of info about the different 4.3's and what they did with 'em, but i cant tell from that if the 2 mentioned engines can interchange blocks (incl. block, pistons, conn. rods, crank, oil pan, cam... pretty much take the heads and intake from the bravada's engine and put that on the block from the other engine)

 

Everything you need to know is right there in that link DV posted. There are other methods of identifying a block than just casting numbers. I've found taking the engine apart and actually looking at what I have to be fairly effective.

But being that I am such a "nice" guy..........

As far as the heads and intake, they will bolt onto any 200, 229 or 262 Chevy 90* V-6. The oil pickup tube and oil pan will bolt onto any '87-up 262/4.3. Rods and crank depend on whether they are Romulus, MI built or Tonawanda, NY built. You can't mix the two, it tells how to identify which is which in the article. Pistons will interchange, they are basically 350 pistons. There is a very slight difference in pin offset but most replacements are plain old 350 pistons. The older block has to be a balancer shaft engine also to use the cam I believe, BTW the cam in the Bravado is one of the better 4.3 factory cams. The difference between the two blocks as to non-balancer and balancer shaft is so obvious when looking at the timing chain area a blind man could see it plus the big crooked shaft above the lifter valley is sometimes a good clue.

Just an FYI a '94 does not have true "Vortec" heads, GM used the name on their 4WD S series 4.3's before they gave the name to the '96-up engines. Of the pre-96 4.3 heads though the '94's are among the better ones.

 

ty for replying Hippie :thumbup:

nice in depth info about the internals of the block, but really what i'm wondering is if i can take the older engine mentioned above, strip the heads and intake off it, and put the heads and intake from the '94 on the 88-91? block. the older engine was rebuilt and not used much (as was the one in the 94 bravada, that is making a noise now) so i was thinking keep the heads and intake and just switch out the blocks and everything inside them. my only catch is i dont know, and cant tell from that link that was posted earlier, if that interchange will work. maybe the two sets of heads have different combustion chamber sizes and would make a higher than needed compression? mby there's a difference in the cam lobes and the cam wouldnt work? its things like that that i dont know, but i'm betting someone here does

the head gasket came up the same part number on autozone.com, but that only tells me the heads'll bolt on the other block as Hippie said, not if they'll actually work (and not be excessively higher or lower compression, etc etc)

ty in advance

 

All 4.3 heads are 64cc chambers with 1.94/1.50 valves, all 4.3 heads will work on any 4.3 block.

 

IIRC, the pre- "real" Vortec ('96-up, like the 5.7L V8) heads had large chambers- just like their 4" bore, 5.7L counterparts.

The real Vortec heads have the smaller 64 cc chambers.

 

IIRC, the pre- "real" Vortec ('96-up, like the 5.7L V8) heads had large chambers- just like their 4" bore, 5.7L counterparts.

The real Vortec heads have the smaller 64 cc chambers.

The '88-up 5.7 TBI '093 swirl port heads and the iron L98 heads used on 5.7 TPI F-bodies have 64cc chambers and from the info I have been able to find the 4.3 Z and W code roller cam engines also have 64cc chambers. I know they used basically the same 12cc dished pistons and were rated at similar compression ratios in the low 9's which leads me to believe the heads have the same size chambers. '85-'86 4.3's may have had 76cc chambers but it doesn't sound like those are in the equation.

 

The only 4.3L V6 heads I have handy to measure, just now measured ~76cc. C/N 14079248.

My set of 1992 350 Truck 210HP L-05, TBI swirl port heads, c/n 14102193 measured ~76 cc.

EDIT- The above is incorrect, below is the correct measurements.

 

AFAIK, the L98 iron heads are 64 cc nominal.

DoubleVision does a lot w/the 4.3. Maybe he can straighten me out. lol

 

The only 4.3L V6 heads I have handy to measure, just now measured ~76cc. C/N 14079248.

My set of 1992 350 Truck 210HP L-05, TBI swirl port heads, c/n 14102193 measured ~76 cc.

Hmmm, interesting. Hard to argue with "hands on". Never measured mine when I had them, everything I had heard or read indicated them to be 64 so I accepted that as fact. But then everything I had heard or read says Vortec heads are good to .470" lift and the machine shop I took my L30 heads to told me in no certain terms they have seen several sets that would hit at .450". Live and learn. Thanks.

 

sounds like he needs a 350 swap. :mwink:

 

----------------

 

nice to see a discussion goin here

"Hippie All 4.3 heads are 64cc chambers with 1.94/1.50 valves, all 4.3 heads will work on any 4.3 block." ...would this include the cam thats likely in the other block (as far as like, how far the cam pushes the pushrods... i'm not very technical or much into things this far into engines myself lol)

and (i think) hippie also mentioned something about the v8 roller cam engines... if the rockers are standard, would that mean the cam is roller or non roller, or would the only way to tell be by the c/n or just looking?

and as far as the whole debate/discussion about 64cc or 76cc, it seems hippie and cobalt are saying both heads would be the same cc, wether 64 or 76 (seeings how one engine is a 88 or 89 to 91, and the other is a 94, both pre "true" vortec). would that be correct?

 

"Hippie All 4.3 heads are 64cc chambers with 1.94/1.50 valves, all 4.3 heads will work on any 4.3 block." ...would this include the cam thats likely in the other block (as far as like, how far the cam pushes the pushrods... i'm not very technical or much into things this far into engines myself lol)

and (i think) hippie also mentioned something about the v8 roller cam engines... if the rockers are standard, would that mean the cam is roller or non roller, or would the only way to tell be by the c/n or just looking?

It appears that IF you have the VIN "Z" engine in the Bravada, the cam in the older, non-balance shaft engine you have would be compatible w/the ECM of the Bravada. This would mean that the older engine could replace the Bravada engine, using the Bravada intake and other accessories.

If the Bravada has the VIN "W" engine, the cam is enough different that there may be problems w/the ECM calibrations. And I don't think you can use the Bravada cam in the early engine- but there could be a way to do it that I'm not aware of. This would mean that the older engine couldn't be used as-is to replace the Bravada engine. You might be able to use parts from the older engine to fix the Bravada engine, but there were differences throughout the years that may come into play preventing the use of some parts, depending on exactly what was needed.

and as far as the whole debate/discussion about 64cc or 76cc, it seems hippie and cobalt are saying both heads would be the same cc, wether 64 or 76 (seeings how one engine is a 88 or 89 to 91, and the other is a 94, both pre "true" vortec). would that be correct?

I believe that would be correct, but there are other things besides the cc of the combustion chambers that need to be addressed. The older engine has adjustable rockers, the Bravada does not. The cams have different base circle diameters that could cause issues if different heads/rocker arm types are exchanged between the engines. Also there are several other differences between the heads that may or may not hamper the older heads being used on the Bravada or vice versa.

 

....there are other things besides the cc of the combustion chambers that need to be addressed. The older engine has adjustable rockers, the Bravada does not. The cams have different base circle diameters that could cause issues if different heads/rocker arm types are exchanged between the engines. Also there are several other differences between the heads that may or may not hamper the older heads being used on the Bravada or vice versa.

The link DV posted addresses those issues. It's starting to sound like mixing and matching different year 4.3 parts can turn into a mess very quickly if you don't do some serious research.

 

I can`t honestly say I ever measured the chambers, but I can say what I`ve seen by my own experiences. I`ve built many a small block chevy, and the only reason why I`ve jumped on 4.3 V6`s is because of two reasons.
First the vehicles I`m dealing with cam from the factory with them. my 1992 chevy step side daily driver I wanted power and mileage so I focused on adding a cam, higher compression and other odds and ends to it, the pay off was over 20 mpg on the interstate. Next is a 1989 GMC Jimmy 4x4 I gave $150 for. Sticking a small block in one of these is no fun, and I already knew I could build a 4.3 with the right pieces and make it scream so I didn`t see the reason to do a small block. As for chamber sizes, From what I could tell, the early 4.3`s, like the 86 model my nephew came across and asked me to look at it had chambers on it identical to sbc smogger heads that appeared to be 76cc. The swirl port heads I`ve seen and sometimes used had a different chamber design and looked to be around 68cc. I was wondering myself about the Vortec heads I just got with this newest 4.3 I picked up. I have 2 pairs of these heads, one pair is 1997 and the other is 1998. I noticed the chamber of the 97 heads looked somewhat larger. Even so I didn`t measure them I would say they are around 68cc`s as they aren`t small enough to be 64. The 98 model heads I have appear to be 64, the chamber is shallower in places. Info from various web sources such as Hot Rods build up of a 4.3 says the chambers of the swirl ports measured at 68cc`s. The SBC will always be my engine of choice, however, I decided to branch out somewhat. I like a challange and that was another reason I went to 4.3`s. The one in my daily driver is impressive power wise, it revs faster than gangbusters and has killer torque. I`ve busted more than one V8 tail on the street with it too and surprised a few people. Most that ride in it swear it`s a 350. To keep this post from getting any longer I`ll do another and list the mods I did.

 

Bored .030 Decked .010. Rotating Assembly balanced.
4 valve relief flat top speed pro coated skirt pistons. 1.560 comp height.
.015 in the bore at TDC.
.030 thickness head gaskets for .045 quench distance.
Swirl port heads mildly pocket ported. Ferrea necked down 1.94 intake valves.
Isky springs, locks, retainers.
Isky hydraulic roller cam Duration @.050 .204 intake .209 exhaust.
Lift is .450 intake .465 exhaust.
Crane replacement hydraulic roller tappets.
Comp cams heat treated push rods.
Milodon double roller timing set.
Comp cams 1.6 ratio self guiding roller tipped rockers.
Edelbrock performer TBI intake.
TBI fully ported. Venom Injectors. Adjustable fuel pressure regulator with vacuum compensator. TBI pod spacer.
MSD Spiral core wires. MSD blaster coil.
Stock exhaust manifolds, dual exhaust, turbo mufflers.
5 speed tranny.
Factory horsepower specs were 160. Now I`d estimate it has around 210.
I was trying to achieve 2 goals, excellant torque and fuel economy.
I`d say I achieved that.

 

Remeasured the swirl port TBI heads c/n 14102193 and in the daylight and measuring a couple times, I get right at 68cc.

So, if this crosses over to the 4.3L heads- as I'm guessing it does- they should also be 68cc nominal.

The 1986 4.3L head from before, c/n 14079248 that I measured at 76cc, remeasured at 68cc as well. My apologies for posting my hasty readings last night- the problem is on my end, the syringe I used is 10cc and not 12cc that I always used in the past, so I 'read' 6 syringe volumes as 60cc when it was really 72cc.

This just leaves the question as to what the other c/n 4.3L heads measure, including the "real" Vortec heads from 1996-up.

 

No need to apologize Cobalt, I figured your measurement of them was more accurate than my eye is. A long time ago when we were all still playing with the old camel back heads I had a couple sets of 461`s come my way and it was obvious they had smaller chambers. I can see why now as some of these heads came on the 283. Since I`ve looked at so many different small block chambers I pretty much just ball park figure it. And I kind of doubt if chevy ever bothered to measure the chambers after production tolerances set in, as the factory was rather careless when it came to some tolerances like tipped block decks, cams that were off, etc.
I wasn`t surprised when I seen some heads chambers get measured and each chamber was found to be a different size.
I guess the factorys just figured "Close enough" was good enough.

 

Rule #1: Never assume. Changes a couple 4.3 plans I had a bit. Good thing I hadn't picked up heads yet.

 

me-> :boxing: <-yall

lol

so yeah, the head gasket come up the same part number, the intake gaskets one has a plugged off part and the other dosent, but seem to be the same..

and i was thinking the blocks and everything inside the block (block, pistons, rods, crank, cam, oilpan [if same shape as the bravada's W engine) could be swapped as a unit with the older Z engine, until some of the posts between this post of mine and the last lol :sweat:

i'm not a internal engine brainiac, dont know alot (or even much) about rebuilding and such, and dont have a way to get around (my '88 nissan with a wore out trans just decided to sieze engine on me the other day), nor much money to rectify that situation. but i do have this '94 bravada available, and the rebuilt older Z engine (c/n's mentioned in 1st post), that i can get for $300. i'm even still trying to get someone quite knowledgeable with internal engine noises to come listen to it to be sure it is something internal engine related, but incase it is.. i need to know if this other engine'll work, how much of it might work, or how to tell exactly if it will (or what parts of it will) work or not.

 

Might be best to just look for a running "W" code out of a '94-'95 S-10/S-15 4 x 4. Plenty of them out there for cheap.

 

I would have to agree.

To use the Z engine's internals to repair the Bravada is fraught w/pitfalls, IMHO. Unless you can verify all the differences between the engines can be worked around, I'd be leery.

For one main thing- you do not yet know what (if anything significant) is even wrong w/the Olds. That would be where I began, but barring that, an engine that would be compatible w/the ECM of the Bravada would be what I'd be looking for in order to do an entire engine swap.

To begin with, see what the cam specs are for the Z engine, and compare them to the Bravada's cam specs. This will tell you most of what you need to know to swap them out.

The other thing that comes to mind, is if the intake side of the Z engine heads are compatible. I have no reason to think they wouldn't be, except for some mention in that article about the heads and their differences.

 

The other thing that comes to mind, is if the intake side of the Z engine heads are compatible. I have no reason to think they wouldn't be, except for some mention in that article about the heads and their differences.

Good point, the heads on my piece of scrap iron "W" code engine have a clearance notch at the top of the intake runners for the injectors on the MPFI used on the W's.

 

Might be best to just look for a running "W" code out of a '94-'95 S-10/S-15 4 x 4. Plenty of them out there for cheap.

i'm in FL, and seems EVERYTHING (including what used to be a $500 used car) costs more here... which even reaches to used axles for a '98 wrangler ($1k) and engines (900-1500+) so yea, with my current budget (making less than $150/wk) the W engine option is kinda out >.<

anyone expert happen to live in FL and could perhaps come listen to the bravada? i've been trying for 1+ weeks to get someone from work to come listen to it to see what he thinks, to no avail. maybe someone could come and have a listen (if they happen to be close enough)

it could be something like the flywheel bolts came loose, we really dont have any idea. the original noise my dad said was a valvetrain noise, but he couldnt tell where so he just parked it to avoid dmg to the engine he'd had rebuilt less than 10k miles before (i'd have taken it back to where it was redone by, but he didnt and it sat for 2 yrs). the guy that rebuilt it said to use only 20-50 oil and premium fuel... so i'm thinking perhaps he didnt know what he was doing all that well, or maybe he didnt do the whole engine / do it right.

i need wheels, i cant pedal this dang bicycle with my knees and back as they are, and i cant afford a engine from the greedy arse junkyards around here... and certainly cant afford to pay someone to do this with the 75+/hr. labor rates around here >.< :smash:


mby i should buy 'im a case of beer or 5 gal of premium fuel for his souped up crotch rocket(s) lol (the guy from work)