My Build Thread (Sort of)

[mechanicalman]

Originally Posted by engineer_gregh

Couple of hundred more miles and I was not happy with the way the truck ran. It seemed to run hot and was underpowered compared to a big block I had owned in the 80's. So I found someone I trusted to rebuild the engine. I don't have the space, tools, or experience to do it myself. Once torn down we discovered 6 402 pistons and 2 396 pistons, 4 burnt valves with bent push rods, and a crank that was so far out of tolerance it couldn't be turned. Just behind the rear lobe on the cam there was a grove cut all the way around. Believe it or not the truck actually ran ok and didn't skip at all. My mechanic has been rebuilding engines for 30+ years and was amazed it ran at all. So the rebuild begins.

65's and 66's used a grooved rear cam journal.

"the 1965 and 1966 big block 396 had unique rear cam bearings and required a grooved rear cam journal, most cams you buy currently are not grooved, the groove can be cut on a lathe in the last rear journal on the later cams , centered ,and its about .188 wide and .125 deep, if the cam is cut,for that oil groove the standard cam bearing can be used".[/size]

http://www.chevytalk.org/fusionbb/sh...hp?tid/311489/

I believe those heads raised the compression (98cc heads). I believe the stock heads would have had larger chambers.

[engineer_gregh]

I don't believe the new cam was grooved so now I'm concerned that I'll have problems in the future. Mechanicalman I hope my engine builder knew what he was doing. I've put about 4K miles since the rebuild with no issues. The gearing and transmission will be a next year project. I would like to have more power out of the hole but the truck runs and drives so good that I just can't justify spending that much money right now. The only addition I've made lately was to add a CPP rear sway bar. It did improve body roll but it seemed to make the truck ride a little rougher. The suspension is less forgiving with rough roads.

[Tom Vogel]

[QUOTE= Just behind the rear lobe on the cam there was a grove cut all the way around.E]

That cam was specific to a 1965 396. That groove was for oiling on a 65 396 block which is different than later years BBs.

Sorry, didnt see post #26.

[mechanicalman]

Originally Posted by engineer_gregh

I don't believe the new cam was grooved so now I'm concerned that I'll have problems in the future. Mechanicalman I hope my engine builder knew what he was doing. I've put about 4K miles since the rebuild with no issues. The gearing and transmission will be a next year project. I would like to have more power out of the hole but the truck runs and drives so good that I just can't justify spending that much money right now. The only addition I've made lately was to add a CPP rear sway bar. It did improve body roll but it seemed to make the truck ride a little rougher. The suspension is less forgiving with rough roads.

That grooved cam was for 65-66, not sure even all of 66; you can't use a non-grooved cam in a 65-66 block. It is ok, however, to use the grooved cam on a later block like you were doing albeit not necessary at all.

No worries, the 3969854 block was for 69-72 396/402/454 2 & 4-Bolt that uses a non-grooved cam. You have the right style cam for your block.

Usually a sway bar will make it ride rougher. If you hit a bump straight on, like a speed-bump or drainage deression, it won't make a difference. You will notice when you hit a speed bump at an angle and go through a drainage depression at an angle that the vehicle will lurch back and forth sideways.

That grooved cam was for 65-66, not sure even all of 66; you can't use a non-grooved cam in a 65-66 block. It is ok, however, to use the grooved cam on a later block like you were doing albeit not necessary at all.

If you used these pistons-
http://www.summitracing.com/parts/sl...make/chevrolet

I figure your compression to be around 8.5:1, perfect for the cam you selected. Unless you used steel shim head gaskets, or had your heads milled then you are close to 9:1.

[mechanicalman]

Originally Posted by engineer_gregh

I don't believe the new cam was grooved so now I'm concerned that I'll have problems in the future. Mechanicalman I hope my engine builder knew what he was doing. I've put about 4K miles since the rebuild with no issues. The gearing and transmission will be a next year project. I would like to have more power out of the hole but the truck runs and drives so good that I just can't justify spending that much money right now. The only addition I've made lately was to add a CPP rear sway bar. It did improve body roll but it seemed to make the truck ride a little rougher. The suspension is less forgiving with rough roads.

Keep in mind that the TH400 has a 2.48:1 first gear ratio and the 700R4 has a 3.05:1 first gear ratio with a .7:1 overdrive.

The 4L80E has a 3.06:1 first gear, BTW, with a .75:1 overdrive.

I'd put in the trans first then address the rear end gears seeing how much lower the first gear is on the over-drives. For instance, if you had a 3.73:1 with the T400 you would have a 9.6:1 overall 1st gear. If you had the 3.73:1 with the 700R4, you would have a 11.2:1 1st gear.

With the 3.42:1 that you have now, with 700R4 you have 10.43:1 first gear.

T400 third gear 1:1 with 3.73:1 is 3.73:1 gas guzzler. With 700R4, 3.73:1 is 2.61:1 ratio highway cruiser. With 4L80 is 2.78:1 cruiser.

I think you will find after you change the trans that you will want a posi anyway so then you will have to change the carrier. Have you seen these style diffs? A posi that does not lock up when you don't need it.

http://www.summitracing.com/parts/dtl-913a315/overview/

[engineer_gregh]

Mechanicalman I appreciate all the great advice. I'm still running the original 3.08 right now. The rear end and transmission is a next spring project.

[EdSevered]

On the bright side, it doesn't look like she needed any body work. She sure is purtty. -Ed

[engineer_gregh]

Thanks Ed. Honestly I went above and beyond what anyone else (normal driver) would have done to the truck. Wheels & tires, rebuilding a transmission that would have probably lasted if left alone, sound proofing the cab, upgraded alternator, long tube headers, bigger cam, three angle valve job, etc.. are what I wanted, and I'm sure that most on this board would have done. I'm building the truck to keep and I want to know that I can take it on long trips with no major issues. Making it mine, is another way to say it.

[PIG-TECH]

wow sharp looking truck. love the shine on the paint job. i am waiting for my garage to be built. and then i get to start fixing mine up

[engineer_gregh]

Updated the wheels and tires. Grandkids like 'em!

[9teen69]

Looks sweet , really nice truck!

[Big Block]

Beautiful truck.

[engineer_gregh]

Thank you.

[72swbcamo]

You have beautiful grand children. God bless them. Nice truck too.

[Red71gmc]

I have a 402 in my new purchase that runs really good, but is no power house by any means. I believe it is all stock.
Are you happy with the power improvement of your upgrades to your engine?

[Riverdog57]

Love the Truck !!! Love the long bed .