73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: dumbucket1 on May 29, 2009, 10:42:18 am
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I have a 87 truck with a 305 with a bad rod knock. Also have a 305 from a 79 el camino laying around that runs great. Can I just put the tbi intake, distributor, etc onto the old motor, drop it in and call it a day or is there going to be more to it? Jeremy
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The intake won't just bolt on without some modification to the two center bolt holes on each side. They are at a different angle on the 87-95 heads.
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Crap I forgot about that. How about if I put the 87 heads on the older block, any other problems?
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No problems if you switch intake and heads.
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Elongating the holes isn't a big deal. Get a carbide burr and stick it in your die grinder. You'll be done in minutes.
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I have a 87 truck with a 305 with a bad rod knock. Also have a 305 from a 79 el camino laying around that runs great. Can I just put the tbi intake, distributor, etc onto the old motor, drop it in and call it a day or is there going to be more to it? Jeremy
You are going to run into a dipstick-left side exhaust manifold issue between the 79 block and 87 stock truck manifolds. Please disregard if you run headers....
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Exactamundo on the dipstick thing; i ended up making a "sleeve" out of a spare dipstick tube and then screwing in a flattop hexbolt to keep everything sealed up.
Current plan is to drain the oil every week to measure how much is in the pan----will refill if the oil looks clean.
Will post pictures as soon as the whole fiasco is over and taken care of. We're almost there.
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I actually worked out a solution after I decided to go with headers. GM made an adapter plate to convert the exhaust manifolds on the left side so you could put all the bolts in and seal it from leaking. I was just going cut the adapter plate where the dipstick tube would normally come through and then bend the tube straight. Then I found a deal on a complete dual exhaust system all the way back with headers included.
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Thanks zieg and stewart I had not thought of the dipstick either and no I'm not running any headers.
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Also the 87 motor has a knock sensor where as the 79 motor does not.
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The knock sensor just screws into the coolant jacket. It makes no difference. There are several different dipsticks you can use.
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I gave that knocking 305 away today and the guy thinks he is going to roll a new bearing in that rod and put a new oil pump in and be ok. Wonder how long before the new bearing spins too.
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60-90 seconds
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i think there is/was a pan available that has the dipstick going directly into the pan---not from the block into the pan.
This pan was stock (maybe) on some gm cars but am not sure----haven't had time to do research---so i decided to do my seal up plan.
There may also be aftermarket and/or custom pans available with "stand alone" dipsticks.
You can also always modify a stock pan---my suggestion is to take a, say 4"x6" piece of lexan, and make a "window" on the side of the pan so you can see how much oil is in the pan. Will provide more detailed plans later. Or have a dipstick going directly into the pan by drilling a hole etc.
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I just did one of these swaps and just had to get an $11 dollar dipstick and tube. Problem solved. There are also universal dipsticks out there that you can use.
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Please describe the swap in great detail as i found there was little to no room to work with.
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OK, i did a little investigating and i came up with GM Part# 464607. This pan has the stick going directly into the pan on the drivers side and they supposedly came in malibus only (?). This should be what you need; i may look into myself if time permits.
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I have a driver-side dipstick on mine, and I see the end has been cut off a little below the top FULL dot. Can I just any SBC dipstick in there and not worry about it hitting the oil pump or soemthing? I'm not sure why the dipstick was cut off but it concerns me a little.
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I have the knocking motor out. I'm researching what it would take to put a 400 in it instead of the good 305. I would like to keep the tbi.
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Not much other than a 400! Good swap!
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I have a driver-side dipstick on mine, and I see the end has been cut off a little below the top FULL dot. Can I just any SBC dipstick in there and not worry about it hitting the oil pump or soemthing? I'm not sure why the dipstick was cut off but it concerns me a little.
i'll get back to you on that one (as if i would know).
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Ok I decided to use the good 305 and save the 400 for another project. Couple questions though. Are the tbi heads worth the trouble of swapping onto the 79 motor? And after pulling a valve cover on the 79 motor I discovered roller tipped rockers with 1.6 stamped on them. What exactly do those do and will they mess with the trucks computer?
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1)RE: tbi heads: probably
2) RE: 1.6 rockers: probably not. Why not just ditch the computer? My bad---i just re-read your original post.
Please keep us updated and hopefully discuss any little nuance you feel is important(as i'm in the midst of swapping a pre-80 305 also); i especially am interested in your dipstick solution; You could try that part# recommendation above.
3) Sux, i will, hopefully, get back to you, or maybe not.
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Ok I decided to use the good 305 and save the 400 for another project. Couple questions though. Are the tbi heads worth the trouble of swapping onto the 79 motor? And after pulling a valve cover on the 79 motor I discovered roller tipped rockers with 1.6 stamped on them. What exactly do those do and will they mess with the trucks computer?
Roller tipped rockers are a good idea for any OHV engine. The 1.6 rocker simply multiplies the cam lift a bit more over 1.5:1 rockers (and also increases valve velocity). Unless the cam is already a bit too big for the TBI to handle, I'd say no they won't cause any problems. But you should verify that the rocker tip sweeps across the CENTER of the valve tip. Most people think that 1.6:1 rockers are a simple bolt on affair (the major magazines are mostly to blame). The pushrod length may need to be changed.
Also, according to the teachings of the great David Vizard (I'm sure you guys are sick of me mentioning him, LOL), unless you are certain that 1.6 rockers on the exhaust will achieve the results you want, stick with 1.5:1 rockers. You reap most of the gain from high ratio rockers, with minimal drawback, by using them on the intake only. The exhaust side is more sensitive to changes in duration rather than changes in lift.