As all fairness goes I am up for an opinion in my new build.  I aquired a 1970 Chevy C20 from a friend (for free, which is the best) who had no knowledge of the truck.  Once recieveing the title I began the task of finding out what it had.  The motor, old and tired, is a 454ci.  Runs but runs very poor and not the orginal motor.  Turbo 350 tranny that needs rebuild due to leaking, with a NP205 transfer case behind that(leaks as well).  Dana 60 rear end and Dana 44 front both with 4.11 gears. Truck has bald street tires and reeaaaallllly bad rattle can paint job.  For this project I am looking at pulling the 454 and replacing with a 350.  Placing truck on 6 inch Rough Country suspension kit with 35X12.50 X 15 BF goodrich Mud terrians. I know that I need lower gears for these tires and would like to throw in some OX lockers as well.  I would also like to keep the turbo 350 and np205 after I rebuild them.  Once done this truck will recieve the body and paint job that it deserves.  But like I said I am up for all opinions and past mods people have done.  Keep in mind that this truck will be used as daily driver to work (5 miles one way) weekend playing at the beach and in the hills.  And when the weather is nice towing the 21 foot bayliner to the local ocean dock.  Any advice would really be helpful.  
Thanks Nick
Oak Harbor, Washington  

Well I would suggest that you rebuild the 454 as the added torque would let you get by better with only 4.10 gears and 35's. A properly built desmogged 454 can be a strong engine even in mild form and if you raise CR ratio to at least 9 to 1 and use 89 octane or better fuel and timed it right it would not be too hateful on gas for its size. (smogged 454's have lower compression and conservative timing) A THM 350 can handle a 454 if properly rebuilt but you do need to include a aux tranny cooler with rebuild.  

Well like I said this is my project truck.  I had one other mud truck that I loved but blew out rear end several times due to improper engine, tanny, rear end combos. It was a 92 Chevy K1500 with a stroked 383 with NVG4500 NP235 tansfer and GM 10 Bolt rear end.  Bad idea yea I know.  Oh and IFS up front.  I loved that truck just as much as it broke on me and I dont want to make the same mmistake again.  I want something that is very dependable and if that means changing every component on the this truck I will.  I just want to play and have fun as much as possible and not worry about the combo choices that I make this time.  I will eat the breaks that I make for being to hard on the trail but not the breaks cause of poor choices.  

I would rebuild the parts you have as it gives you more to work with potential wise for the money.  

Also I am thinking that I need to replace the wiring harness in this truck.  Most of the wiring is totally gone and half of the dash gauges dont work.  Would it be easier to buy a complete painless wiring harness or just start from scratch?  

the wireing on that truck is so simple ya can fix whatever it needs with ease.  

mudb8_:
the wireing on that truck is so simple ya can fix whatever it needs with ease.

Yes, that is one of the beauties of those old 4x4's.  

As the thinking process goes and the look at the truck I have yet another question for the gurus of this forum.  This truck HAD a drop in plastic POS bedliner that held water very well.  Not liking the water fill up I removed the plastic POS.  Once grinding the well rusted bolts from the plastic it was lifted and set next to the garbage can.  Underneath the heap of platic I found the most distrubing thing ever.  The entire bed it pitted with holes and rusted metal.  Not a good idea if you are going to carry anything in it.  And since 1970 parts are not the easiest thing to find I plan on welding a faltbed to attach to this truck.  Yes I can weld with the best of them.  I have seen many people build custom and stock flatbeds for toy's and ranch trucks and I would like to know what people like and dislike about thier flatbeds.  And yes I understand that it is a flatbed and will have to tie everything down.  I want to know the details of how this welded piece should have gone here instead of there cause of this reason.  That is what I want to know.  

Nothing wrong with a good flatbed made properly but I would strongly suggest that you build it as a frame to have a wood floor (use ruff cut oak or pressure treated lumber) as it makes a far better floor in long run. Also you want to bolt flatbed to truck frame not weld it so design it accordingly.  

yep, I also use aluminum decking, I like the looks, its a little heavier than the wood.  

I have a tilt trailer with diamond plate metal deck. I wish it was wood. Diamond plate looks pretty but not very practical at times if you use bed a lot.  

As soon as I am doing asking all these questions that snoman usually answers for me I think that I will have to make a trip to let him play around in the truck.  So here is another for you snoman since your last replies have been very good.  This truck has the stupid behind the seat gas tank.  But I have opted to put in full roll cage with 5 point harness and racing seats.  Problem being the DAM tank is in the way.  Has anybody heard of someone moving the tank to a different location.  And where did they put it and what type of tank did they use.  

Well I have somewhat of a answer for you. GM offered aux fuel tanks on trucks 67 thru 72 from factory. I know because I bought a 72 in 74 that had them. They mounted under bed between frame rail and bed just behind cab and had a filler cap on side of bed just behind cab at about same height as one on cab. (the tanks rear edge was few feet for rear axle as it was located well forward under bed) It had a valve on floor to switch between tanks and a switch on dash to select which tank to measure/gauge. I do not know how hard it would be to find some of these tanks but they were sturdy welded ones not stamped steel and even had screw in drain plugs. The aux tanks held about 17 gallons each. Thought I never did, I did debate a few times removing my tank behind seat for the extra storage space and using aux tanks only but never did. Because of safety concerns in some crashes, tank was removed from cab in 73 but where it was put in front of rear wheel between frame and bed and made of cheap stamped steel proved to be a bigger problem in crashes than being in cab and in 88 the moved tank behind frame rails.  

yep, I have two of em with factory auxilary tanks and one with bed mounted  dual tanks not factory of course..  

GM supported up to two factory aux tank which gave to a total capacity of around 55 gallons. When on a trip I used to run tank behind seat dry as it would give you a warning in that you could hear the tank to start to suck down a bit when it stated pumping air which compressed a lot more in pump so volume increased being removed faster than vent on tank could deal with it. When this happened you quickly switched tanks and there was no interruption in power from engine. With aux tanks there was very little warning other than loosing power. It was nice on trip and I usually used the main and aux tank as they both filed on drivers side and I would even use two pumps to fill them at same time. (that used to get some funny looks)