|11-06-2011 05:56 PM|
I still have the motor .. I took it out of a 1970 one ton.
Had it rebuilt .. And put it in a 1987 one ton van ....I am almost 100% sure it has the 76cc heads . And 2441 sounds familiar:??? Block was the 3970010 block
Four bolt main . Not a nice job getting a tappet cover off a van ;; BUT I may have too now ::))
Unless some one had an extra 300 horse sticker around .
Or the motor had the covers changed .. And those sticker were on them :????
But this van had no power steering .. No power brakes ..Standard trans with three on the tree . the tappet pans had no holes for pcv valve . No pollution pump .. Nothing . Just a four barrel carb .
So I thought maybe the extra horse power was because it did not have to drive anything like an auto transmission; lose anything for power brakes etc .
Because this motor had no hookups for my newer van .. I had to use an intake and valve covers for a 84 350 to make it hook up
But when the guy rebuilt it he said he used the ORIGINAL specs for a 300 horse motor. So he must have thought it was a 300 horse motor too..
So I guess I ""ASSUMED"" LOL there was different cams for the higher horsepower motor .
Now I have to look up the 041 casting /
Thanks for the help .. Maybe I will get this right in the end
|11-06-2011 04:04 PM|
In the 50`s 60`s and early 70`s, power was measured by "Gross" meaning on a dyno, with no accessories such as water pump, etc. It was set for it`s best timing curve for power, the carb was set rich and no exhaust.
In the early 70`s that was changed to "net" which was timing set "safe" which means low as you could go and it run, the carb was set lean, full choked exhaust system, full accessories. So when a engine was done on a "gross" figure and made 300 horses, you put it on the "net" and that figure dropped to about 210. I never seen a 300 horse 350 with 441 heads, all the 300 horse 350`s I ever seen had 041 casting heads and some had 492`s. The 441 casting smogger head had large 76cc chambers and these usually came on engines making around the 250 mark only in "gross" specs. However, no, a carb don`t make a 50 horse difference. Cams were also different. The Cam used in 300 horse 327`s used since the early 60`s was used well into the 70`s and came in almost all base engines and some medium performance engines. That cam was used in the 283, the 307, the 327 and the 350. Later on when emission standards got more strict this cam was dropped from production even so it just about had round lobes.
|11-06-2011 11:28 AM|
It was a four barrel motor ..
On the tappet pans it had 300 horse ..
IF a 1969 with the same same heads or cc heads had 250 horse with a 2 barrel carb ....
Does the four barrel alone make up the extra 50 horse ..
OR does the 250 horse motor have a different cam ect along with the two barrel vesus the four .
Also the van was a standard ..
And this motor came from an auto
|10-26-2011 07:00 PM|
Had the seated hardened when I bought them off a machine shop going out of business.. They were bare heads on a shelve ,,
I bought them done and ready to go .
The block is large journal.. And the casting was used for 302-327-and 350 in 1969.
So I guess I could even build a 302 .. If a person could find 302 flat tops .
Or 283 - 125 over
|10-26-2011 05:35 PM|
|DoubleVision||You`ll have to confirm what year the block is, if it`s a pre 1968 block it`s a small journal crank and I don`t know of any small journal 350 cranks out there. Usually 9.5:1 is the safe limit on pump gas, but those of us adventurous enough to set a tight quench distance can get away with 10:1 compression. The 492 are decent heads, however, they don`t have hardened exhaust seats for use with unleaded gas if you didn`t have it done. In time the valve will pound away the seat. You can use a additive called lead substitute that comes in a bottle that does a little to help but not much. But using a bottle of it at every fill up gets expensive. If I were you I would sell the camel back heads and get some vortec heads. Vortecs are 30 horses over the camel backs.|
|10-26-2011 05:14 PM|
you are helping alot to say the least ..
I use to have a book that told what the compression ratios were .
64cc . flat top .. 350 ;; Say 10 to 1 ( Not sure )
68 cc . dish .....350 ;; 8.5 to 1 etc..
Lent the book never got it back ..
I have to buy a crank .. pistons .. cam etc anyway
So will it make any difference in compression if I rebuild it as a 350 versus a 327 as far as keeping the compression within gas pump limits .
The heads I have are already rebuilt and ready to go .
So I need to keep the motor and cam within specs to match the heads ; IF that makes any sense .
Maybe have to use 350 dish versus flat top
Thanks in advance
|10-26-2011 03:43 PM|
yes you can get more horses with smaller CC heads. The less CC in the heads the higher the compression you will get, resulting more horsepower. You just do not take 283 heads and put it on a 327 or 350. You raise the compression but it can't breath because of small ports and valves.
3986336 71 350 76CC
3932441 67-72 327-350 76CC
They are fairly matched
3991492 are 64CC high performance heads. It will wake up the engine.
hope this helps
|10-26-2011 03:10 PM|
Thanks for the info ..
I guess I was looking at the wrong end of the code .
Here is the deal LOL
Helped a guy put this motor into a chev pickup a few years back .
He took it out of a write off pickup :??
Was told it was a rebuilt 327 .
Now the harmonic pulley came loose and ruined the crank .
There was no center bolt in the crank. or no hole with threads to put a bolt.
It was pressed on I guess ::????..
Anyway the motor has two different heads .
One is 3986336 .. and the other is 3932441 .
I want to rebuild this motor..
I have a set of 3991492 chevy heads to go it ;so at least the heads will match .
If I put the smaller heads on this will my horse power go up much
|10-26-2011 01:33 PM|
Code Year CID Vehicle HP RPO Trans Carb Comments
HM 65 327 Corvette 365 L-76 4-spd 4-Brl Holley, HP solid cam, A/C
HM 68 327 Impala 250 L-73 TH 400 4-Brl Hyd Cam
HM 69 350 Impala 250 L-65 TH 350 2-Brl Hyd Cam
|10-26-2011 12:53 PM|
I have a small block chev with a casting number of 3932386 ,
This number shows up as either one of the above engines .
The code on the front pad makes no sense to me .
TI105HM . The other number is 19111632.
When I look up the cast number TI105HM ...
There is no such code
There is every thing from TBS to TXC but no TI1
Thanks in advance ..