502 into a '87 350TBI truck

Has anyone put a 502 or similar Big Block motor into a 350 powered truck? My main concern is the header issue. The information for the GM 502 HO recommends headers with 2"x30" primaries. But Jegs only sells headers like that for old muscle cars. They dont sell any truck headers with those dimensions.

Also, how long would a 700r4 hold up against 450hp and 550ft/lbs of torque? I would not be racing or competing with this truck, so I'm hoping i can baby it for a while on the 700R4 I have now before upgrading.

any and all input/advice welcome. Thanks
-Turk  

With out any kind of mods to the stock 700r4 the tranny will not hold up to that much power even the turbo 400 one of the better trans made they can only handle 450 ft/ib your tranny will last about a week take it out and have it rebuilt and upgraded with every titanium upgrade avalible then you will have a very solid trans and wont have to worry  
Need a Big Block

i have no idea about header issue, but the 700r4 will handle the power only if you have it rebuilt using all new and high performance parts and you have proper gear ratios in your axles so as not to create excessive trans slip and heat.  
Solid axle chevys can't be beat!
My dream truck: 73-91 chevy 3500 crew cab srw with dana 60/14bolt, 6 inc long travel lift with KING shocks, 37 inc tires and a 24v cummins diesel, nv5600 and np205

If I were you I'd go TH400 route, with a little bit of a build it should hold easily. I've seen stock 400's hold 500/500 combos all day, but it may just be luck.  

Your trans question is answered.  For the headers, try calling Summit Racing Equipment's tech line ( 1-330-630-0240 ).  Header fitment is listed for stock vehicals.  If your truck is lifted, it may be possible that a car application could fit.  They may be able to answer your header question, call them, they are very helpfull.  

Hooker may not have them listed, they do have or can make them. I stuffed a 475hp 502 in a 86 shorty several years ago, that's where I got them, Super Competition Hooker, If I wasn't 3000 miles from home I could probably find the part Receipt, I had to trim the frame.
the 400 tranny outlasted the engine. I put a trans-go -2 shift kit in it, drilled the plate for quick firm shifts, If it is pulled down to manual 1st it slams into 2nd at 6000rpm and squalls the tires, you won't hurt the 400 with the 502. if you do it was a few quarts low on fluid. I did however scatter a 208 t-case planetary drum and twisted the pinion shaft off a 14 bolt, I put in the rear and a dana 60 up front.
the 700 will need a shift kit and an upgraded drum and clutch packs. as long as you stay out of the throttle when it's shifting, it'll last a while. check out TCI  
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