Engine swap diary

[Stewart G Griffin]

Also, the v-8 throttle cable and Edlebrock bracket seems to work pretty good.  i think a stock setup is better, but i might leave this custom setup on for a while just to see how it goes.


Also, the carb apparently needs the choke;  i didn't think i would need it because it's so warm around here now, but it does seem to need it.

[Stewart G Griffin]

Yay!  Stock cable has arrived.  Zieg is the man of the hour.

Probably can't do too much work until the weekend though.

[Stewart G Griffin]

v-8 air cleaner housing works with custom throttle bracket----it interfered with the stock v-6 bracket.

i will probably leave the aftermarket bracket on for a while just to see how it works.

[zieg85]

Get it running and driving and if you decide on getting the correct 4.3L air cleaner housing let me know.

[Greybeard]

If the carb on it now works that's good, I was guessing that the other carb may not have been drained when you parked it waiting for the swap. This new high quality water they give us that poses as gasoline does not weather very good. Use some fuel system cleaner (I have recently learned to love SeaFoam in my seldom used garden tractors). Even the looks of the one in the recent picture you posted looks a little rough. In my experience a carb seldom goes totally bad unless it warped or cracked. Although some carbs where bad when new.

It sounds like a lot of work what you are doing. What was said earlier is so true about getting burnt out on a project, that is the position I am in. I spent SOOOO much time, energy, and money swapping a 454 out for a 355 in my truck and putting in a four speed (along with a hard to find four speed steering column) in place of the automatic and changing the 203 t-case for a 205, that now that it works, I stopped doing anything on it and it sits with a mostly brand new engine that has less than 1000 miles on it and is ten years old now. Sitting is the worst thing that can happen to mechanical stuff. I should have done the body and suspension work first it seems so it would be drivable when I got the engine in. Actually it is drivable now, but with gaping holes in the floorboards and dusty gravel roads it's no fun to. Now the frame is rusting out from under it. I had high hopes to get to it this summer, but that hasn't happened yet with all the other crap this farm needs first. I bought a welder to do the body work over a year ago but haven't had time to do it. Now I believe it would be easier to swich out the cab for one that doesn't need so much done to it. Even my A-pillars have rust holes in them.

I am getting close to hi-jacking... 

[Stewart G Griffin]

WE are almost there---i had other business i had to attend to over the past week.

You know those clips that go over the throttle arm on the carb to secure the accelerator cable?   $9.75 at Advance Auto.  i think i'll try the salvage yard instead.  Rock auto has them for .21 cents but the shipping is $5.75.     i think Dorman may have discontinued them.         In my haste to get the truck running, i left mine on the valve cover.  Well, these 4.3's shake at idle(big disadvantage compared to the v-8's).  Clip gone.

[Stewart G Griffin]

Ok, we are basically finally done.  i took the truck for a short ride.  i can't tell the difference between the 4.3 and a 305 besides the fact that the 4.3 vibrates like heck compared to a v-8 at low rpm.  at about 1100 rpm and up it's ok.  Remember, these earlier 4.3's don't have the balance shaft.

i think now it's just a matter of tweaking;
i found an throttle arm clip at the salvage yard.
i think i need a new carb regardless.  Looking at JET.
For the exhaust, i decided to use the stock y-pipe, Walker pt #40423 and a flex pipe running to a muffler that is chained to the frame.  i'll get the exhaust done right at a shop asap.

Special thanks to Zieg 85 for supplying the mounts which really made the swap possible at all.   i also ended up using the 4.3 throttle cable, which Zieg also supplied, because somehow i broke the v-8 cable's plastic clip that fits into the pedal at the end.   The v-8 cable could probably work though with the edlebrock cable bracket for this swap.
   

[Stewart G Griffin]

Update:
i basically did this diagram for my own reference:



Lotsa room:



Notes: i got the Mr. Gasket air cleaner because i needed the truck running fast and they had them at the local parts store, i am planning on getting a K+N when this one plugs.
i really like the flexible braided pump-to-carb line.  One advantage to using one is i can run many different carbs with it----if i need to run B.O.P. quadrajets, not a problem.  Very easy to disconnect and connect.

UPDATE:
So i basically got the thing running in October and i actually had 3 carbs on it before finally getting the Jeg's reman---which runs well.   i actually had a Rochester 2G on there with an adapter and it actually ran pretty good----until it  flooded out and i decided since i didn't know the rebuild history on it, that it would be better not to use it.  The other two quadrajets i had---the one that came with the engine didn't idle very well and the quad that was original to the truck just didn't idle at all----probably sat around too long.   So i decided to try a Jeg's reman.

Other notes:
The v-6 radiator hoses bolt right up to the v-8 radiator.   The v-6 mounts were actually pretty easy to put in--- only took a few minutes to drill new holes (3 on each side) in the frame.  It's gathering all the other do-dads that is time consuming for this kind of swap.   The v-8 power steering lines can be used with the v-6 if you take the frame clip off and pivot the lines towards the engine.

Thanks again to Zieg for supplying the mounts and  v-6 throttle cable!

However, i think this engine is hosed---it was making to many strange noises and is recently using coolant---i'm loosing almost half the radiator every 40 miles and i can see steam coming out of the exhaust pipe.

i'm looking for a suitable replacement and may rebuild this one---if it's rebuildable.   i may have to run an electric pump as these carbed blocks are not easy to find and may no longer be available from GM?   So i may have to run a newer 4.3

[Jim_Hensley]

Dont bother with a K&N filter , they don't filter worth a shoot and  its useless on a 4.3, just get a regular round paper air filter.

[hatzie]

v-8 air cleaner housing works with custom throttle bracket----it interfered with the stock v-6 bracket.

i will probably leave the aftermarket bracket on for a while just to see how it works.

Get an air cleaner with a velocity stack off a 70's or 80's G series Van with a Rochester quad...  It's not really a velocity stack.  It's a sheet metal spacer ring that raises the air cleaner 2-3" off the carb for cable and hose clearance in the tight G-Van engine compartment.

http://www.ebay.com/itm/Air-Cleaner-Spacer-3-Holley-Quadrajet-Ford-GM-OEM-GM-truck-/262392296222?hash=item3d17ccb31e:g:jjIAAOSw3mpXE~Ny&vxp=mtr

[Stewart G Griffin]

UPDATE:

i don't know if anyone cares, but stock iron 4.3 v-6 heads fully dressed weigh 43 pounds.  Stock iron 305 heads weigh 46 pounds.   So the weight savings isn't in the heads.  These were called vortec heads but i don't think they are true vortecs?   Also, i'm ASSuming most v-8 iron small block heads are going to weigh about the same irregardless of displacement.


i got the heads, pan and timing cover off.   No major damage or cracks that i can see so maybe this one can be rebuilt, fingers crossed.   But it won't be for a while as i already ordered and received a reman 4.3 from GM, part#12361243.   About $1450 no core charge.  It does not have provisions for the mechanical fuel pump so i'll have to run an electric.

v-8 air cleaner housing works with custom throttle bracket----it interfered with the stock v-6 bracket.

i will probably leave the aftermarket bracket on for a while just to see how it works.

Get an air cleaner with a velocity stack off a 70's or 80's G series Van with a Rochester quad...  It's not really a velocity stack.  It's a sheet metal spacer ring that raises the air cleaner 2-3" off the carb for cable and hose clearance in the tight G-Van engine compartment.

http://www.ebay.com/itm/Air-Cleaner-Spacer-3-Holley-Quadrajet-Ford-GM-OEM-GM-truck-/262392296222?hash=item3d17ccb31e:g:jjIAAOSw3mpXE~Ny&vxp=mtr

Thanks for the tip.

[zieg85]

I care, I want to see if the MPG's were worth going to the V-6

[hatzie]

I've owned an 85 C10 with the LE9 305 4BBL and a 1987 C10 with the LB4 4.3L TBI.  Both with the SM465 Low + 3 transmission.
The 4.3L actually got noticeably lower fuel mileage than the 305.  I always figured it was because the 4.3 was woefully under-powered in the lower RPMs.  There's no replacement for displacement.

[Stewart G Griffin]

I've owned an 85 C10 with the LE9 305 4BBL and a 1987 C10 with the LB4 4.3L TBI.  Both with the SM465 Low + 3 transmission.
The 4.3L actually got noticeably lower fuel mileage than the 305.  I always figured it was because the 4.3 was woefully under-powered in the lower RPMs.  There's no replacement for displacement.

The last 4.3 didn't do so well on mpg, getting almost as good as the 305 and 350, but i think it was hosed from the beginning and i should have realized that from the beginning.

The 305 does make a little bit more power and at a lower rpm BUT i think 4.3 and the 305 are basically in the same ballpark in terms of power.  The later 4.3's make even more power.   The 4.3 is about 125 lbs. lighter and has less rotational and reciprocating mass as well as less friction ( i think?----less bearings, cylinders, lifters).  So we'll see.

[Stewart G Griffin]

i am getting closer to just going to the dealer and signing on the line.  i think most of these reman or new engines were designed to be installed by the dealer for a customer and not really designed for the do-it-yourselfer.

If i was going to do this all over, i would have either bought a crate 350----because then i could have had this truck running in about 8 hours, because i did it before----because everything bolts up, because small block v-8's are so popular.  4.3 just isn't that popular let's face it, and there's a lot of quirks to it to slow you down.   Although the mini 4x4 crowd seems to love it.   OR gone down to the dealership and gotten me a nice colorado or something with a duramax and then treated the square as more of a hobby.  As it is now and has been i use the square as my main transportation, along with my other cars, and for hauling so i need the thing running ASAP.

Anyways,
To do list:
1) Purchase timing cover dowel pins, oil pickup screen, oil primer tool, melonized distributor gear (because this new engine has a roller cam), harmonic damper intallation tool, oil pan gasket,  Moroso engine storage bag, oil pickup screen installation tool.

2)  Install timing cover dowel pins:  Apparently these 4.3 replacement blocks don't come with timing cover dowel pins---i'm theorizing because later 4.3's used the plastic cover which doesn't use the conventional pins?    And i can't get the pins out of the junk 350 block so i figured the easiest way is to just buy some new ones.

3) Install previous stock timing cover.  Here i couldn't really use any small block timing cover because the 4.3 uses a smaller damper which means the timimg tab is in a different spot than most.  Worse comes to worse i could use any small block cover, establish TDC and make or adapt another timing tab but that's too much work.

4) Polish snout of harmonic damper, then Install harmonic damper.  BTW this one is not easy to find.  It's a 6.25" diameter  i think the buick v-6 also uses the same one.

5) press pickup screen into new oil pump.  They did include a new oil pump with the engine.  Here the pickup is a Melling 55-S2, same as v-8 small blocks.
6) install oil pump.

7) install oil pan.  Clean if necessary.

8 Install flexplate

9) Establish TDC for cylinder #1.

There's more, but i think this is realistic goal for now.