Engine build

[jlmohr76]

Looking for thoughts on this. I got a 350 motor with 305 heads on it. The heads are 416 castings and the price was right, free!!! Wanting to rebuild the motor to put in my truck just not sure if those heads are worth using. Trying to keep the cost down so I'd like to use what I have. Pros-Cons to these heads? Anyone run these heads with much luck before? Not needing a killer motor, just daily driver with as much low end torque as I can get.

 

[HotRodPC]

Pro on the heads, Higher Compression, Con on the heads, they have small ports and don't breathe worth a damn though that'll give low end grunt

 

[jlmohr76]

Thought about upgrading the valves and doing some porting. Biggest concern is keeping the compression pump gas friendly.

 

[1987 GMC Jimmy]

I daily drive my car with the very same set of heads. It's got a 305, though. They're about the best set of factory 305 heads made, but that's not saying much. The valves are 1.84/1.5, I believe. You can get a port and polish, and that'll help them out. For a 305, that's about the third or second best way to go, but I wouldn't think so with a 350. If you're not worried about having a power monster, you could probably source a good set of fuelie/camel hump heads on Craigslist for cheaper than a cylinder head shop would work those heads for you.

 

[HotRodPC]

ehhhh, I see where you're going with that suggestion, but I see 2 things wrong wit it. #1, it does suck to lose the accessory holes. #2, the suggestion to save machine shop cash isn't likely to happen for 2 reasons, #2a when you do find those fuelie heads, they need worked over too, #2b, let's not forget about unleaded gas and the need for hardened valve seats, that's going to cost machine shop cash.

If machine shop cash is a problem, and not having much to lose, I'd experiment with those 305 heads. Get a Dremel tool and gasket port the bitches, and get some valve grinding compound and disassemble the heads and lap the valves and replace the valve seals. He can use them budget Wee O Five heads for now and later on when the budget supports some worked over Vortecs or aftermarket aluminum ready to bolt on then that's what I'd do. In all honesty, I'd just go for the Vortecs now and have them worked over at the machine shop and be done. They'll keep the good compression the Wee O Five heads will offer, bigger valves and much much better breathing for low to mid range powa !!!

 

[Green79Scottsdale]

If you are working on a budget, use the heads. Porting will help these along more than most realize. I have seen a couple of flow charts on 416's that are better than Vortecs. Yeah they require work, but it is possible. Being they are on a 350 you can reshape the combustion chamber and unshroud the valves. Of course this is only relevant if you are doing the work yourself. They are no worse than the 70's/80's smogger heads, I think.

Just do cost break downs of all the different situations you could go, and go with the one that most appeals.

 

[1987 GMC Jimmy]

ehhhh, I see where you're going with that suggestion, but I see 2 things wrong wit it. #1, it does suck to lose the accessory holes. #2, the suggestion to save machine shop cash isn't likely to happen for 2 reasons, #2a when you do find those fuelie heads, they need worked over too, #2b, let's not forget about unleaded gas and the need for hardened valve seats, that's going to cost machine shop cash.

You're right. Most of the fuelies don't have accessory holes, but I think they got them in '69, which was close to the end of their tenure. Either way, to find a set of fuelies with accessory holes right now will be tough. I agree with you fully. Those things may need to go straight to the head shop, too.

 

[jlmohr76]

I might play around with the 416 nothing to lose. I can always upgrade later. But of course now I'm thinking more and more about doing a 383. This motor would go in a 4x4 daily driver.

 

[HotRodPC]

I might play around with the 416 nothing to lose. I can always upgrade later. But of course now I'm thinking more and more about doing a 383. This motor would go in a 4x4 daily driver.

If you do the 383, DO NOT use the 305 heads. The compression will be to high for pump gas.

 

[jlmohr76]

Most likely stick with the 350

 

[Rusty Nail]

I bought a pair of 416s for my 350 but haven't put them on yet.
That will be my second time to build that combo.
The first time I replaced a set of factory heads on an early-mid 80s Suburban with hopped up 416s. The result was fantastic.
The were "light bowl-blended", milled flat, with a "3-angle" on the stock valves.

My second set built for a 1980 - 350, I specified that I wanted my guy to "zap the flash" out of them and "match a set of springs". He said he had a bucket full...
Okay. Otherwise standard rebuild. I was shocked thinking his price of $270 was high.
SINCE THEN , I have read moar about the 416 and gather they flow rather well compared to other stock offerings regardless of what you may hear to the contrary. If I was gonna dump any more money into my $50 heads, I would have the Exhaust only, fitted for bigger valves. That would be the great bang for the buck, Exhaust flow needs all the help in can get, based on my rather extensive research. I consider porting the Exhaust side only.
I thought I was on a hurry to swap em out but it didn't turn out that way. I very likely will spend more in them later.

They're great heads from my REAL-LIFE ACTUAL EXPERIENCE.

 

[SkinnyG]

I have 305 heads on my 350, but they are 450 castings. They really don't look that much different, visually, than any other smogger heads. Apparently they are garbage heads. But - they had valve guides that were bang on spec, and they were free.

I ported the snot out of the bowls, and smoothed everywhere I could. I back cut the valves, and radiused the chamber side of the margins. I used a surfacing disc on the combustion chamber (with some used valves) to take off all the sharp edges.

The engine is .020" over, flat top four-eyebrow pistons, 0.025" in the hole, with a 0.015" steel shim head gasket. The cam is 231°@0.050 with 108°LSA (very lopey, idles at 8inHg in drive), and runs just fine on 91 octane, with 36° full advance. Compression works out to about 10.9:1

It can be done.

But....

If you're going to spend money, buy Vortecs or something aftermarket. Only do 305 heads if they are in good shape and are free.

 

[jlmohr76]

Thank you all for your help! I think I may clean up the 416's and try them on my 350. The heads that are on it now are early 70 350 BUT they have issues. Try out the 305 heads until I can purchase a better set of heads. One thing about vortec do they have the heat crossover for the intake?

 

[SkinnyG]

There is no heat crossover at all on Vortec heads.

That doesn't mean they won't work, it just means that it's not going to be completely happy until it is completely warmed up.

The heat is something you really want with a wet intake like Carb or TBI.

 

[jlmohr76]

That's what I thought and is my only concern running vortec heads. It can get pretty cold here in the winter.