Mismatched heads?

[Mikew88]

Hey guys so I recently got a 305 from a guy planning on using the 416 heads on my c10. However when I got the engine home and started to tear it down I found one head is a 416 the other is a 450so I scraped the idea of using them. My question is will this 305 run decent for another project I have as a temp motor I would still like to put a cam in it mainly to sound more aggressive but I dont want to waste money if it will not run. Guy clames the motor has never been apart but I find it hard to believe with non matching heads

 

[Bextreme04]

Hey guys so I recently got a 305 from a guy planning on using the 416 heads on my c10. However when I got the engine home and started to tear it down I found one head is a 416 the other is a 450so I scraped the idea of using them. My question is will this 305 run decent for another project I have as a temp motor I would still like to put a cam in it mainly to sound more aggressive but I dont want to waste money if it will not run. Guy clames the motor has never been apart but I find it hard to believe with non matching heads

Whats the whole casting number? There are quite a few "416" AND "450" casting numbers you could be talking about. I would personally not run mis-matched heads.

 

[Mikew88]

I'll have to get the casting numbers when I go to the shop this weekend I was under the impression the last 3 were all you needed to I'd

 

[legopnuematic]

My 76 had mismatched heads on it when I got it and the previous owner had the engine installed in 2007 (I had gotten it in 2016) and it ran fine even though there was quite a significant port size difference and a 1cc difference in chamber sizes. January of 2019 I pulled the engine out and did a quick hop up with a set of summit iron heads (dart iron eagle 165) and now revs beyond 4k lol.

 

[78C10BigTen]

My 76 had mismatched heads on it when I got it and the previous owner had the engine installed in 2007 (I had gotten it in 2016) and it ran fine even though there was quite a significant port size difference and a 1cc difference in chamber sizes. January of 2019 I pulled the engine out and did a quick hop up with a set of summit iron heads (dart iron eagle 165) and now revs beyond 4k lol.

How good are dart iron eagles? I just stumbled upon a set...

 

[legopnuematic]

How good are dart iron eagles? I just stumbled upon a set...

Coming up on two years with them being on the truck and have not had any problems with them. Biggest issue is that the pipe thread in the sides are smaller than the OE so the temp sender will not bolt up to them (I moved mine to the intake). In my application the 76 pulls hard to 5500 and under load that's about it (with 3.08's that already about 60 anyhow in 1st) Free revving I saw the tach wing up to 7000 once. Good casting work and machining on them.

They move my 6500lb truck pretty good for the horrible gearing with too tall of tires. For the price I am very satisfied.

 

[Salty Crusty]

As long as the chambers and runners are close to the same size, you'll be fine.

Every single person I know that built up a 305 regretted it. For the cost of a block, you can upgrade to a 350 block and even stroke it if you like.
It's not just the cubic inches that's a problem, it's the small bore which makes it harder for the engine to breathe.

 

[Mikew88]

I got the engine for free I mainly want to use it to get the truck moving while I build a better engine as it's been sitting for the better part of 20 years my only concern is if I'll have issues with reliability with the heads not matching

 

[Salty Crusty]

As long as the chambers are similar size as are the runners, you'll be just fine. I betcha if you had run it before you knew about the different castings, you would have never known that they were different.

 

[Bextreme04]

I got the engine for free I mainly want to use it to get the truck moving while I build a better engine as it's been sitting for the better part of 20 years my only concern is if I'll have issues with reliability with the heads not matching

Thats why I was asking about the whole casting number. There are several different heads with the same last three numbers from different eras. They have different size chambers. If the chamber size is the same, you'll probably be ok in a stock power application. The engine won't run as smooth and probably wouldn't last as long.

 

[Rusty Nail]

416s are WAAAAAAAAAY better than 450s.

Too easy to buy another 416?

They were available with different VALVE SIZES and you would hate to bring home a set with 1.50 valves in it. Heads up.


Get it?


Heads up?

 

[SquareRoot]

It's a 305. Briggs and Stratton couldn't hurt it.

 

[Ricko1966]

As Rusty said 450 and 416 are not even similiar heads buy 1 or a pair of 416s. And a 305 will be just fine for a cheap temporary engine while you save the funds for what you really want.It'll get you to the store and to and from work etc. If it needs more than rings, bearings and a valve job though your better off not building it just putting the money towards your good engine.

 

[Ricko1966]

Hey guys so I recently got a 305 from a guy planning on using the 416 heads on my c10. However when I got the engine home and started to tear it down I found one head is a 416 the other is a 450so I scraped the idea of using them. My question is will this 305 run decent for another project I have as a temp motor I would still like to put a cam in it mainly to sound more aggressive but I dont want to waste money if it will not run. Guy clames the motor has never been apart but I find it hard to believe with non matching heads

There is actually a guy out there racing 305 's. same build on all of them,929 cam a performer intake, Holley 600,headers, all on stock, oil burning used 305's they all run like high 14s get respectable mpgs and he drives daily and too and from the strip all in A body GM's. I think his article title was mighty mouse in underdogs clothing.

 

[Salty Crusty]

We have local roundy rounders that have a class for only 305's.
Works for me, I sold 3 for the same price as I was getting for good 350's.