Not getting much help/useful advice in the Tech forum on this. I'm thinking about purchasing a Weiand 142 in good shape for $500. I had imagined that my 305 heads would have to go, and they did confirm that. However, I've got 64cc regular 350 heads sitting around that could also be used. Smogger heads (1985 truck heads), but that's what I can run for the moment.

Now, I had imagined that with regular 64cc heads on a normal 010 block (not decked or anything) with 15cc dishes would be able to take the boost from a Weiand 142 without a problem. They're telling me over there that without new forged internals, it's more or less guaranteed to blow up.

I know that it's risky running any sort of boost on a stock block, and when it blows up I will build it, it will give me an excuse. But I had thought that with a low compression 350 and the bottom of the bucket Weiand roots blower that the motor could live fairly comfortably for a while. Am I wrong?

 

You don't NEED forged interrnals.

Keep the RPM down and the rods will surive.

Spark knock will kill a forged assembly too, they will only buy you a bit more time. Avoid that and it should work. With lower compression you can use more boost.

 

WEIAND says the mild 142 is fine on a stock motor. I'm in the process of putting one on my freshly rebuilt stock 310. I'm thinking of adding a methanol/water injector to keep things cool and prevent detonation. $500.00 is a very good price. New they are more than tree times that cost!!

 

keep a leash on compression and you should be able to run 5-6psi if the motor is in at least "average" condition.

 

Not really... I'd worry more about your pistons when it comes to boosting stock parts.

 

You have to avoid detonation while under boost.

lower the compression ratio 8.5:1 or lower is best .

Don;t get silly with the boost pressure 6-7 PSI is good.

install a blower friendly cam (recommend Crane HMV-278)

recurve the distributor to limit the total advance travel. and use vacuum advance too. (will need fine tuning)
you want more initial advance 16 to 20 at idle and limit the total advance to about 26-28deg at WOT. Then fine tune in the vacuum advance for cruising and reference the vacuum to the manifold.

Use cooler non projected tip sparkplugs. For 305 heads or old 76cc smogger heads us Champion RV8C plugs.
A holley 3310 works well on this motor use 74 pri and 88sec jets and a big fuel pump. The accelerator pump will need more volume (50cc pump) and a large shooter to work with a blower. (large internal volume to fill.)

Use the best gas you can get 93-94 octane.

Water/methanol injection will allow more boost and timing.

What is the casting number on the 350 heads?

Some are just not worth it. A 441 487 920 or 336 head would be nice (especially with larger valves and home porting ) 882's and 624's suck.