350 cam question

[khan0165]

most 305 heads had 56cc to 58cc chambers, which is similar to L98 heads found in late 80s corvettes.
when used with a traditional factory dished piston, the 58cc chambers can offer anywhere from 8.7 to 9.5:1 compression

it's on the high side, but plenty safe for pump gas. If you plan to use an aggressive cam, you may need excessive timing advance, which will cause detonation with that kinda compression. You would need 91 octane there.

keep the cam mild, you can use high lift, mild duration to have good street manners. You can run 87octane, and make good torque without detonation

 

[SScamino]

Yea 416 305 heads and a 350= fun. I had this as an original combo with a mild unknown cam and a 600cfm carb performer intake shorty headers full exhaust with 3.73s and WOW. Thing would tear it up. Ran on 87 but I always put 93 in it. I could only imagine if I put like an xe262 with smallish stall the thing would've been twice the fun.

 

[-83MONTESS-]

According to the I.D numbers on mine I have 305 heads on my 400. I have heard this is a common "low budget/hillbilly" way to get some power considering my stock 400 heads were probly worse being a mid 70s engine but I would imagine the power curve would fall flat on its face in higher RPMs so I dont understand why someone would do this. I dont ever have mine above 4500-5000 RPMs because I know how low the stock 400's max RPM is so I havent really tested this theory :lol:

 

[khan0165]

Yea 416 305 heads and a 350= fun. I had this as an original combo with a mild unknown cam and a 600cfm carb performer intake shorty headers full exhaust with 3.73s and WOW. Thing would tear it up. Ran on 87 but I always put 93 in it. I could only imagine if I put like an xe262 with smallish stall the thing would've been twice the fun.

... wow, I had the exact combo
mine were "305 HO" heads, 600cfm Carter carb, and 3.73s, and unknown mild cam, ran it on 91 octane. It made butt-loads of torque, chirped all 3 gears, but fell flat on it's face after 5000rpm.
... this was in an 83 Camaro tho, that motor blew up the borg warner 9bolt posi (which was known to actually be stronger than our 7.5 10bolts)

 

[khan0165]

I would imagine the power curve would fall flat on its face in higher RPMs so I dont understand why someone would do this. I dont ever have mine above 4500-5000 RPMs because I know how low the stock 400's max RPM is so I havent really tested this theory :lol:

you are right, this combo is not known for it's high revs. Iron heads with high compression meant they were very easy to knock. You couldn't run a big cam because you couldn't run alot of timing because it would knock. And without a big cam, you couldn't make good power up in the rpms, not that the heads would flow there anyways.

if they were aluminum, you could likely run more timing, thus a larger cam, and it'd be worth it port and install larger valves. That'd be a good rpm motor.

but as is, you had to take advantage of the compression and small ports, and build them for torque over horse power.

 

[megaladon6]

Its not just the compression, the 305heads simply flow like crap.

 

[NY87SS]

Its not just the compression, the 305heads simply flow like crap.

The 416's and 081's will flow somewhere near 200 CFM+ @ .500 lift.
On the exhaust side 120 or so @ .500 lift.
The highly prevalent 882 heads of a 350 which are about the only ones you can get cheap can't even match those numbers.
200 CFM in the intake side can take a motor up to 325+ H.P. with no problem, the weakish 120 on the exhaust will still support that.
3-5 angle grind, some bowl work and your well past 200 CFM intake, 140+ exhaust which is around the numbers the Aluminum headed "L98" are which is a very good budget head. Some real porting beyond the simple bowl work and these heads have flowed numbers matching Vortec heads in stock form which can support 400 H.P.
So they are not shitty heads by any means, its just those with 350 minds have talked themselves into it.

The compression can be a added bonus since most all cheapish 350 heads will be either a 72 or 76 CC head either not flowing as good of numbers or close, but the extra bit of compression does the job.

So based upon cost, 416's and 081's for free are decent. Want more, put about $300 in them and you can push nearing 400 H.P.
Little more money, find some L98 heads and rework those.
Next on a budget with about the same cost as the L98's is the 059 Vortec head.

 

[kewpie79]

Will I need a stall converter with the setup I mentioned?

 

[NY87SS]

No not really.
The stall speed will depend on how much power it'll end up making and where the cam choice puts that power.
The factory stall would be enough, but if you pushed the powerband up then you might want to go up a few hundred rpm in stall speed!

 

[kewpie79]

What intake manifold would I need? I was told by my mechanic that I need a vortec carbureted intake manifold. Is this correct?