[Guest]

On 2009-04-16 20:45, ZacD wrote:


350 heads on a 305 really isn't going to be such a hot setup. A 305 has a smaller bore than a 350 and as such, a set of heads from a 350 will have their chambers and valves somewhat shrouded by a 305's cylinder bores.

350 heads have a far bigger cc chamber and you would lose a ton of compression to put them on a 305

 

[INSANEBA]

Besides, I've never seen a "strong 305" lmao. I've pulled perfect running 305"s and given them away, no need for boat anchors here lmao...

 

[Stepside350]

i dont know???
the 305 i have now i guess is a good powered motor
yet 400 didnt seem that better
with the 400 it ran a 12 sec 0 to 60
ill try with the 305 and see if its close
that"ll get me somewere in the ball park of knowing the power deffrences
just stumped on this 305s power???

 

[ZacD]

That's a fairly rudimentary way of judging what is best for your application.

If that 305 has enough power for what you want to do, just run it.

That said, all small block 400s, as delivered by Chevrolet/GM, were never extremely powerful. They were smogger engines, as were many/most engines produced in the '70s, and as such were low output engines moreso tuned/aimed at meeting emissions restrictions.

That said, if you're going to build an engine, I wouldn't so much as think about a 305. I'd either build a 350 based engine or a 400 small block and, at that, a nod towards the latter if you can find a good core to build.

As I referenced by that engine they built in Chevy High Performance, a fairly simple flat-top pistoned 406 small block with a set of as-cast Vortec iron heads, hydraulic cam, readily-available intake manifold, readily-available carb and cheapo headers made 525 lb/ft of torque. That's more power than most stock big blocks make. That would absolutely roach stomp that 305 in your truck now.

 

[INSANEBA]

I say try to put a cam, intake and carb on that 305 and run it, then make the exact same mods to the 400 and then see the differences. I know personally that the 400 is twice the motor, and thats not just because I own one. I used to swear by the 350 chev, but after putting this one together, I swore I would never start with less than 400 ci again. The mods done to it will show way more than any other small block period. What was the old addage, "theres no replacement for displacement", that being said 305-400, no hard choice to make there... :bigthumb: Not to mention the TORQUE!!!, 305 has NONE and the 400 has a {expletive} ton lol, thats what our heavy @ss rigs need to git-er-done! :

 

[Stepside350]

well i know ill build on a 350 or 400 if i swap motors
yet the 305 was mainly to get the truck rolling
it turned out to be good tho
well thx for the info

 

[Stepside350]

well i know ill build on a 350 or 400 if i swap motors
yet the 305 was mainly to get the truck rolling
it turned out to be good tho
well thx for the info

 

[mudpup98]

what are some ways to identify a 400 smallblock

is there any colors

or codes to see if its a 400???

All 400 SB are siamese Blocks so if you look on the side of the Block you will see humps where the cylinders are at .

 

[Drewz]

Easiest way to spot a 400 is to look at the harmonic balancer. If it’s cut away like an odd shape or weight then it’s a 400. All 350s have a perfect semetrical balancer