262 to 350 crate: help

[MadOgre]

... I might have switched internals now that you mention that. Its been so long I can hardly remember anymore

 

[fussfeld]

I thought the fuel pump was the same ? from my old memory.

One fascinating fact is that a 2.8L starter will fit on the 90 degree 2.8L V6 and also fits on the 4.3 and V8 engines as well. It even turns the 4.3 no prob. Might do the same for a V8 as well!

The fuel pump for v-6's are upside down and as such don't have the vent hole on top. Also the pump to carb line will be different than an 8.

Now, a v-8 pump could probably be used and vice versa if you have the space for it. But check the pushrod lengths. they might also be different between the two.

i think the reason for the upside pump was to clear the crossmember?

 

[fussfeld]

What year and model is your truck? I can dig up P/Ns on motor mount brackets -- both frame side and engine side.

I'm surprised to hear the distributor can be converted. ???

i would like to think that mounts can interchange, but for some reason from the factory they are reversed:

v-8 has the clamshell bolted to engine and rubber mount bolted to frame. v-6 has the rubber mount bolted to engine and clamshell bolted to frame.

My only guess is they did it for vibration?

But since the bolt patterns are identical between the two engine, they should bolt up.

As for as the distributor, i think all you need is an 8 cyl pickup and "star wheel" thing and of course the cap. i think modules would be the same? In my case the engine came with a 6 cyl distributor.

 

[MadOgre]

The fuel pump for v-6's are upside down and as such don't have the vent hole on top. Also the pump to carb line will be different than an 8.

Now, a v-8 pump could probably be used and vice versa if you have the space for it. But check the pushrod lengths. they might also be different between the two.

i think the reason for the upside pump was to clear the crossmember?

Oh ok that's probably vehicle application specific. Interesting. I swear the one I had was the same as any other V8 fuel pump. It was a long time ago though.

I know you can use the V8 pump because the blocks are identical in all aspects except # of cylinders.

Ya the fuel line wont fit because the carb is positioned further back from the front of the engine on the V8

 

[MadOgre]

i would like to think that mounts can interchange, but for some reason from the factory they are reversed:

v-8 has the clamshell bolted to engine and rubber mount bolted to frame. v-6 has the rubber mount bolted to engine and clamshell bolted to frame.

My only guess is they did it for vibration?

But since the bolt patterns are identical between the two engine, they should bolt up.

As for as the distributor, i think all you need is an 8 cyl pickup and "star wheel" thing and of course the cap. i think modules would be the same? In my case the engine came with a 6 cyl distributor.

What vehicle did you have? cause the 4.3 V6 I had was the same as any V8 with the same mounting for the engine mounts as any V8

 

[fussfeld]

What vehicle did you have? cause the 4.3 V6 I had was the same as any V8 with the same mounting for the engine mounts as any V8

The engine i have now originally came out of a 86 c-10 that is/was being parted out.

i'm pretty sure you can interchange mounts with v-8 small blocks, i'm just speculating that the factory reversed them on 6's due to vibration differences between the two engines. The 6 kinda shakes (especially with no balance shaft) especially at idle. While the v8 as you know is silky smooth.

In fact when i first put my 4.3 on my engine test stand it bolted up exactly the same as any v8 small block. i will try to provide a pic a.s.a.p.

 

[MadOgre]

Ya mine was an 85 c10. Maybe its just been so long I cant remember properly. I dunno. I thought the cup mounted the same way.

But I do remember that it was a really really smooth little 4.3 hardly even knew it was running half the time! So you must have some issues with yours?

 

[domino33]

hello all... back again, and finally starting on this project. at the point of buying parts now. decided to buy a motorcycle over summer so i forgot about the truck for awhile

a lot of great advice so far and i think i have a clear understanding of everything i need to purchase:

gm 350/260
engine mounts (oem) rock auto
intake manifold (edelbrock performer eps)
carb, carb to fuel pump line (edelbrock performer 600cfm)
distributer, dis. mount, conversion accs. (jegs hei)
water pump ("heavy duty" aluminum airtex) rockauto
fuel pump (acdelco)
radiator
fan shroud
thermostat
long tube headers, wrapped until i can afford coated (jegs)
flexplate
harmonic balancer
throttle cable, bracket
carb to vac brake booster metal tube
longer throttle springs
plugs, wires


So my alternator will work? What about power steering pump? Also pullies should work too?
Trying to replace as much as I can but not necessarily more than I need to. I'd really like pullies to work even if I have to make them look nicer by painting them or something. Was going to go with the 350/290 but am pinching my wallet at the moment... plus i plan to eventually upgrade the cam in the 350/260 so i think i'd be better off with that anyhow. I didn't mind the 4.3 when I first got it. Seemed quick, responsive, took me where I needed to go.. But I had an oil leak develop in one of the cylinders (p.o. had to have known something about). So engine started misfiring...did what i could to temporarily fix the problem using hotter plugs but knew eventually the engine was going to go... At the same time I think I was also dealing with a head gasket that was developing a leak(or just a very dirty cooling system). Plan to keep engine though as it is original and the first year (or second) for them. So I will attempt a rebuild on that eventually.

As far as setting up vac lines and things with the new carb... is it pretty straightforward? Any ideas on how to set up vac lines, crankcase ventilation, etc?
Also how about the oil pump? will I need a new one?

Any advice will be greatly appreciated. trying to get this done by the new year. I think I covered most everything but it is hard to say. I will also be researching these questions on my own. thanks!!

 

[rich weyand]

Changing the cam out on a brand-new 350/260 out of the truck is pretty easy and cheap. You can use the same lifters and springs.

Changing it out once it is in the truck is a major PITA. Plus you need to change the lifters if the engine has been run AT ALL.

 

[87scotty]

I feel like you can get more power for same money I'm looking at a blueprint 383 400hp 440 tq fully dressed for 4k and I feel like I could pay less for a 355 same power

 

[87scotty]

But I priced everything out and it would cost me more to build it myself than by there crate pisses me off

 

[domino33]

I have thought about many different crates but the gm replacement seems to be the most cost effective right now. unfortunately

Rich- thanks for that bit of info...should have thought about that. really dont want to jeopardize the warranty so i doubt i will change out the cam initially or maybe not at all.. hard decision as im sure thousands of people have faced LOL not really worried about me causing any problems to the engine that i would need the warranty...just don't want to get a lemon crate and have a voided warranty


I am not looking for too much power, just something better than what i had/oem. even if im right at 260hp or so that sounds fine to me as this is a daily driver/work truck to a degree.

 

[85c10owner]

I have thought about many different crates but the gm replacement seems to be the most cost effective right now. unfortunately

Rich- thanks for that bit of info...should have thought about that. really dont want to jeopardize the warranty so i doubt i will change out the cam initially or maybe not at all.. hard decision as im sure thousands of people have faced LOL not really worried about me causing any problems to the engine that i would need the warranty...just don't want to get a lemon crate and have a voided warranty


I am not looking for too much power, just something better than what i had/oem. even if im right at 260hp or so that sounds fine to me as this is a daily driver/work truck to a degree.

The 260hp engine will be way better than your stock engine. Swapping the cam now with void the warranty for sure but I think once you get it going you will find it has plenty of power. BTW, the 260hp and the 290hp engines are the same except the camshaft. The 290hp camshaft is the old 350hp 350 vette cam and really not suited for a truck engine. I had one of these engines in a 65 el camino with a 4spd and was pretty decent once it got rolling but it needs some gears. I cant see paying all that extra money for a 40yr old camshaft either. If you decide to do a camshaft later I`d look into one of the smaller lunati voodoo grinds or possibly the Comp 4x4 xtreme grinds.