Beenz

I'd like to add headers but I think I'd have to go custom,also I'd like to know what problems or common issues you guys ran into .thanks a lot !

joe_padavano

Welcome. This was actually a relatively common swap for the GM trucks with the Olds 350 diesel motor. The 350 Olds gas engine (and most Olds engines, actually) are a bolt-in replacement for the diesel. Headers will be custom.

olds 307 and 403

I actually welded B body frame/motor mounts on my 78 C10 2wd truck. With those mounts, 68-72 SBO A body Flowtech headers fit not bad. One tube very close but didn't touch the frame and tubes just barely touched the A arm bolts. Either the Sanderson or Hedman's shorty headers will fit with plenty of room on a 2wd truck. Both shorties have thicker flanges, 3/8" on Sanderson.I had to use double gaskets to seak and had to cut the cross member with the Flowtech full length headers. Get custom exhaust and use the shorties, there is a lot of room there.

jcdynamic88

i had a 455 in a 79 c10 and used headers for a 76 cutlass w/455 and they fit perfectly,i believe headers for a 76 cutlass with a 350 should fit your truck.i cant think of a reason why they wouldn't.i still have those headers but i believe they would hit the starter on a small block.

oldsmobiledave

https://classicoldsmobile.com/forums...into-what.html


Scroll down in that thread to post #15 to see my 455 T400 install with headers in my 1980 GMC.

Beenz

Thanks for the replies!! Got a dumb question also ..where the hell is the thermostat housing on this 68 SBO ?? I can't find it for the life of me and can't find anything on Internet either .

Beenz

Does the stock diesel manifold turn down to the flange ? I think I read that some where . The ones on mine do .just wondering if flange gaskets are different?

Beenz

Nm about the housing hahaha glad it wasn't a snake !

Beenz

looking for some insight,tips,secrets ect .on this swap ..thank you all .

oldcutlass

Which part of the swap are you looking for?

joe_padavano

I'm assuming the Olds gas engine replaced a defunct Olds diesel. Ask specific questions. We don't know what information you are looking for, exactly.

Beenz

yes you are correct ,ok ive replaces
d chevy dipstick tube but the olds is tough getting it to seat over the two flanges is driving me crazy ..wasting tons of time with this ..ugh

Beenz

so first is the dam oil dipstick tube ! haha its a nightmare getting it installed

Beenz

had the worst time with replacing the oil dipstick tube on the 69 350 rocket stock exhaust mani . so i ordered 3 different tubes from 3 different companies and none of them fit right so the one i could get to fit ,but it was a loose fit i just used oil resistant high temp rtv on it ,letting it cure over night .we will see how well it holds up ...

Beenz

what a great cutlass!!

Beenz

well im having an issue with the stock fuel pump to edelbrock carb now. got the dipstick in have the intake manifold and carb in just dont want to spend 50 bucks on the kit if i dont have too .im getting a new fuel pump soon but for now im going to roll with the stock pump ,also my temp sending unit is difficult to find the right one its a L shaped two prong sending unit ??

svnt442

Got a picture of the sending unit?

Beenz

ive been checking this out might just save the day ,thanks

Beenz

ill take one tomorrow and post it ,thanks

Beenz

I just switched from a Rochester 2bbl manual choke and cast manifold to an edelbrock performer 1406 carb electric choke and the edelbrock 2711 intake , the motor is non EGR ,the distributor is accel performance replacement and accel super stock coil , the trans is an automatic th 400 . I feel good about the install of intake and carb all has been torqued fuel line is good electric choke is wired well , now need to know what to do with vacuum.. here is a pic of the motor as I bought it there were two vacuum hoses connected the sto manifold one in front one in back ,where do those come in to play now ?

Beenz

Ok,edelbrock 2711 intake installed ,1406 carb ,all vacuum hoses and fuel hoses tight and connected . gas in the tank fuel in the filter electric choke hooked up to ign slot on fuse box ,electric choke set, mixture screws set out two turns throttle cable hooked up. Battery is good, starter good wont fire over . it has an accel timed vacuum distributor accel, super stock coil , 8mm wires ,new plugs .I'm going to run some tests in a couple day like spark plug test light ,voltometer ect. but was wondering where to start looking first here is a pic of it stock and a couple pics now

oldcutlass

Engines need air, fuel and a well timed spark. Make sure there is power to the coil + terminal, look down into the carb and work the throttle and see if there is fuel. If you removed the distributor, make sure the rotor is pointing to #1 when the number 1 cylinder is on the compression stroke.

Beenz

didnt remove dist. carb is getting gas.

Beenz

just looking at the stock set up .. since the distributor is vacuumed to the intake should I not have it now connected to the timed vacuum port on new carb? would that cause it not to fire over ? if that is the case where do I find two non timed vacuum ports ? do I need to get an adapter for the intake like on the stock intake ?? hmm

Beenz

just looking at the stock set up .. since the distributor is vacuumed to the intake should I not have it now connected to the timed vacuum port on new carb? would that cause it not to fire over ? if that is the case where do I find two non timed vacuum ports ? do I need to get an adapter for the intake like on the stock intake ?? hmm

svnt442

No, no. That wouldn't keep it from firing.

Beenz

can u see any thing on my set up that seems out place ? like vacuums, fuel line route ect ?

oldcutlass

Ok, the carb is getting gas. Have you checked for spark?

Beenz

havent had a chance to check spark yet . it would fire over before didnt run well because of the old gunked up carb but it would run

Beenz

checked with a spark plug light and none are getting spark , it ran before the swap ? I broke my multi meter but will get a new one in the AM ,when I do what should I check in order ??

oldcutlass

Do you have power at your coil + terminal with the key in both the start and run position?

Beenz

just got my voltmeter wire ,im going out to check the power to coil,so just need to make sure im getting power to the positive post ? what if im not where do i check next ? what if i do would it be the plug wires

oldcutlass

Before jumping to conclusions lets troubleshoot.

Beenz

ok so looking more into it now gas is not getting to carb but the inline fuel filter is full of gas but no squirt of gas shoots in the carb when i pull the throttle ....the new coil i had put in tested at 9.90 so its bad put the old one back on that tested good . how do i go about trouble shooting this gas issue ?

oldcutlass

If you look down into the carb with the engine off and operate the throttle, do you see fuel spraying in there? Are you getting spark now?

Beenz

yea now i get spark but not fuel squirt in carb

oldcutlass

Disconnect the fuel line at the carb and point it towards a container while someone cranks the engine, see if it pumps fuel. If so then I'd look into the carb. Take the top off and see if there is fuel in the bowl. Could also possibly be the accelerator pump.

Beenz

so when i got the truck it was a hot mess ,the fireing order was not 18436572 at all but it ran, not well but the carb was shot to hell so i replaced it and coil,wires, cap, rotor, plugs, intake ??? so now i do the correct order and it is wrong no spark?? spitting gas mist and occasional fire ball ,how can it fire with no spark ? so my question is if they put a different cam could my fire order be different? and if so how do i re find that order ??

Beenz

jeez,haha so now plenty of fuel ,no spark ,well at least not lighting up my
tester.. . so i noticed the fire order was wrong so i changed it i had a pic of it as it was but that was lost when my phone broke .so now its way off ,wondering if a new cam was put in and changed the fire order ?

olds 307 and 403

No. Make sure your firing order is counter clockwise and number 1 is in the right spot. Make sure your point gap is right and not burned or is this the Accel electronic distributor?