are 96 305 heads and block the same as previous years

dhashigu · 08-09-2007, 11:00 AM

I have a 96 Chev with a 305, is there any difference between the heads on my engine and the heads off a 1988-94 305? also is the block the same as 85 and up, small block. Also is the flex plate the same for a 4L60E, as it is for a turbo350., 70r4 etc...

mrjohnwayne · 08-09-2007, 11:28 AM

The heads are the biggest difference. They are a "fast burn" design that started with the vortec motors in 96. The blocks are basically the same. As for the flexplates. The only difference between the flex plate might be the bolt circle for the convertor but I think they are all the same. If you are thinking aboutr changing heads I would not. Those vortec heads are going to be much better than any other stock head. If you go aftermarket that is a different story.

dhashigu · 08-09-2007, 12:06 PM

My idea, was to take a 305 from my 85 chev swap heads, change gaskets, get the heads machined and have it ready, so that when i am ready to swap engines out of my 96, it will be alot faster.
the 96 has a 305 that got cooked, and those 88-95 heads are easy to finde around here, the vortecs are still hard to comeby. i guess i'll just keep my eyes out. worse comes to worse (if the heads on the 96 are ok i'll just use them)

75K30 · 08-09-2007, 12:31 PM

You are gonna take out a burned up 305, and install another 305 that is older?
Seems like a bunch of work for an engine that makes around 170 BHP.
Instead of spending time and money on a smal displacement V8, why not take advantage of a larger displacement engine. Put at minimum a 350 in it for the same amount of work, and about as much money as the rebuild.
I know you are probably going to say that " the 305 from the old ruck ran fine" , but consider the amount of labor involved VS. calling up a vendor, having the complete engine delivered, and dropping it in. That is as simple as it gets now a days.

dhashigu · 08-09-2007, 12:46 PM

i figure i could get the other engine in for price of the gasket set ($85) and a valve job ($250), and the rest is just my time. i bought the truck for $800 (from my work), and at the moment its all i got (in the way of drivable vehicles). It's one of those things, moneys tight, got my first kid coming, and the banks run when i look their way.
Although i do agree, 350 is a way better motor. I only have one good 350, and i was saving it for my 1970 gmc.
Do you know if the 350 gets better fuel mileage then the 305?

Sneakysportsman · 08-09-2007, 05:35 PM

96 and up heads are a rare wether 305 0r 350, There are several things you have to look at,
Some L31 (96 up 305& 350) engines came with roller lifters, some have flat tappet lifters, the trouble here is ECM reading of the cam sensor, Vortec heads only have 8 small intake bolts that only seal the water passages in front and rear, If you 96 engine was cooked the heads might be cracked in the middle where there is no water crossover from the intake, it may not leak until you unbolt them. Ir your engine came with roller lifters chances are that that 85 block was not set up internally for the retaining plate and dog bones that keep the lifters from turning on you cam. You cant put roller lifters on a flat tappet cam. I can go on and on but those two blocks have to be premated with parts before installation and getting out cheap doesn't even fit into the picture. Be Safe TAKE YOU TIME AND DO IT RIGHT THE FIRST TIME. I KNOW, see that pic under my name? I can pull that motor from that 4X4 truck in 1 hour by my self, How? I bought cheap parts that cost me an extra $1000 for a new cam and lifters and gaskets and valve train parts. I chose the machine shop to do my heads the cheapest and have had them reworked twice, because they didn't have a clue about Vortec heads. Thats a 95 with retro-fited vortec heads and oversize valves. Its not impossible it can be done but DO THE RESEARCH FIRST.

dhashigu · 08-10-2007, 10:10 AM

Wow, i had no idea that gm changed the block that much in 96. I have always run carbed engines, until last winter when i got a good deal on this truck, and the manual trany in my 83 packed up.
Out of curiosity, where is the cam sensor located?
Thanks for the info, and saving me the trouble, and frustration, of finding this stuff out the hard way.

Sneakysportsman · 08-10-2007, 08:31 PM

The actual sensor is located in the distributor. You must use the OEM cam or one that has been tested to fit and run with this sensor. For less than a grand you can put a good block back into this vehicle but shortcuts will cost you several grand in the end.

dhashigu · 08-13-2007, 10:36 AM

Thanks again for the info

Sneakysportsman · 08-13-2007, 09:29 PM

Also, there is a crankshaft position sensor on the bottom of the timing cover on a 96 and up that utilizes a small trigger placed on the crank.

08-09-2007, 11:00 AM	#1
dhashigu Full Member Join Date: Jul 2007 Posts: 29	are 96 305 heads and block the same as previous years I have a 96 Chev with a 305, is there any difference between the heads on my engine and the heads off a 1988-94 305? also is the block the same as 85 and up, small block. Also is the flex plate the same for a 4L60E, as it is for a turbo350., 70r4 etc...

08-09-2007, 11:28 AM	#2
mrjohnwayne Senior Moderator Join Date: Apr 2005 Location: Texas Posts: 3,710	The heads are the biggest difference. They are a "fast burn" design that started with the vortec motors in 96. The blocks are basically the same. As for the flexplates. The only difference between the flex plate might be the bolt circle for the convertor but I think they are all the same. If you are thinking aboutr changing heads I would not. Those vortec heads are going to be much better than any other stock head. If you go aftermarket that is a different story. __________________ John Wayne 2000 F-350 7.3L Powerstroke 4x4

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08-09-2007, 12:06 PM	#3
dhashigu Full Member Join Date: Jul 2007 Posts: 29	My idea, was to take a 305 from my 85 chev swap heads, change gaskets, get the heads machined and have it ready, so that when i am ready to swap engines out of my 96, it will be alot faster. the 96 has a 305 that got cooked, and those 88-95 heads are easy to finde around here, the vortecs are still hard to comeby. i guess i'll just keep my eyes out. worse comes to worse (if the heads on the 96 are ok i'll just use them)

08-09-2007, 12:31 PM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	You are gonna take out a burned up 305, and install another 305 that is older? Seems like a bunch of work for an engine that makes around 170 BHP. Instead of spending time and money on a smal displacement V8, why not take advantage of a larger displacement engine. Put at minimum a 350 in it for the same amount of work, and about as much money as the rebuild. I know you are probably going to say that " the 305 from the old ruck ran fine" , but consider the amount of labor involved VS. calling up a vendor, having the complete engine delivered, and dropping it in. That is as simple as it gets now a days.

08-09-2007, 12:46 PM	#5
dhashigu Full Member Join Date: Jul 2007 Posts: 29	i figure i could get the other engine in for price of the gasket set ($85) and a valve job ($250), and the rest is just my time. i bought the truck for $800 (from my work), and at the moment its all i got (in the way of drivable vehicles). It's one of those things, moneys tight, got my first kid coming, and the banks run when i look their way. Although i do agree, 350 is a way better motor. I only have one good 350, and i was saving it for my 1970 gmc. Do you know if the 350 gets better fuel mileage then the 305?

08-09-2007, 05:35 PM	#6
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 290	96 and up heads are a rare wether 305 0r 350, There are several things you have to look at, Some L31 (96 up 305& 350) engines came with roller lifters, some have flat tappet lifters, the trouble here is ECM reading of the cam sensor, Vortec heads only have 8 small intake bolts that only seal the water passages in front and rear, If you 96 engine was cooked the heads might be cracked in the middle where there is no water crossover from the intake, it may not leak until you unbolt them. Ir your engine came with roller lifters chances are that that 85 block was not set up internally for the retaining plate and dog bones that keep the lifters from turning on you cam. You cant put roller lifters on a flat tappet cam. I can go on and on but those two blocks have to be premated with parts before installation and getting out cheap doesn't even fit into the picture. Be Safe TAKE YOU TIME AND DO IT RIGHT THE FIRST TIME. I KNOW, see that pic under my name? I can pull that motor from that 4X4 truck in 1 hour by my self, How? I bought cheap parts that cost me an extra $1000 for a new cam and lifters and gaskets and valve train parts. I chose the machine shop to do my heads the cheapest and have had them reworked twice, because they didn't have a clue about Vortec heads. Thats a 95 with retro-fited vortec heads and oversize valves. Its not impossible it can be done but DO THE RESEARCH FIRST.

08-10-2007, 10:10 AM	#7
dhashigu Full Member Join Date: Jul 2007 Posts: 29	Wow, i had no idea that gm changed the block that much in 96. I have always run carbed engines, until last winter when i got a good deal on this truck, and the manual trany in my 83 packed up. Out of curiosity, where is the cam sensor located? Thanks for the info, and saving me the trouble, and frustration, of finding this stuff out the hard way.

08-10-2007, 08:31 PM	#8
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 290	The actual sensor is located in the distributor. You must use the OEM cam or one that has been tested to fit and run with this sensor. For less than a grand you can put a good block back into this vehicle but shortcuts will cost you several grand in the end.

08-13-2007, 10:36 AM	#9
dhashigu Full Member Join Date: Jul 2007 Posts: 29	Thanks again for the info

08-13-2007, 09:29 PM	#10
Sneakysportsman Senior Member Join Date: Jun 2007 Posts: 290	Also, there is a crankshaft position sensor on the bottom of the timing cover on a 96 and up that utilizes a small trigger placed on the crank.