mastaflymason

Hi everyone, I'm currently in the process of swapping a 350 from a 305 into my 1990 Trans Am. I have a couple quick questions I'm hoping you guys can help me with.

First is the flex plate isn't the same size. I have a Turbo 350 transmission if that matters. The 305 I believe was from an early 80's pickup truck, and the new 350 was a late 80's or early 90's crate motor. What flex plate do I need to buy?

Also there is something coming off the oil filter on the new engine and I'm not sure what it would be for. I don't have anything like it on my 305 but I'm not sure what to do with the lines, cap them off or what?

Also is there anything else that won't swap right over to my 350? I already put on the intake and a few other things but I haven't gotten my alt, ps, and that kind of thing swapped over.

Pictures attached, one is the flex plate on the new 350 and one is the two oil lines on the 350 that I don't know where they go.


Thanks all!!

86Z

iTrader: (4)

thats an oil cooler, you can remove it and get a standard oil filter adapter for it. you need an 86+ 1 piece seal flywheel

NoEmissions84TA

iTrader: (1)

Correction, it's the oil cooler ADAPTER that runs to an oil cooler.

86Z

iTrader: (4)

my bad i forgot adapter although i said you can replace it with a standard oil filter adapter... but thanks for taking the time to correct me

five7kid

iTrader: (14)

'86-up used a 1-piece rear main seal, as your picture shows. To get the seal to slide over the end of the crank, they had to make it all round, which required elimination of a counterweight that the 2-piece rear main seal engines had outside of the crankcase. The equivalent of that counterweight was moved to the flexplate (or flywheel), so they changed the bolt pattern so weighted and unweighted flexplates couldn't be mismatched to the engine they are supposed to go to. So, a flexplate for '86-'92 f-body V8 will work for you. That is assuming your TH350 torque converter will bolt to the 153-tooth flexplate 3rd gens used. If not, you'll probably have to get a flexplate for an '86-up light truck, which will be 168 tooth. 153 and 168 tooth flexplates used different starters, so you'll need the appropriate starter for whichever flexplate you end up using.

If you have the correct intake manifold for your 350 and whatever induction system you'll be using, shouldn't be. 1987 was the year they moved to different intake manifold bolt angles for the center two bolts on each side of the intake. '86-earlier won't fit on an '87-up engine, and vice versa (directly, anyway - you can modify them to work.) Except for '86-up Corvettes and crate engines with aluminum heads - they didn't change those intake bolt angles.