Retrofitting a pre-computer engine in a G=Body

[Oldscarnut]

I ran a 204/214 cam with .065" quench on a 9.6 to 1 Olds 350. It pinged and just wasn't fun to drive around town and the filled crossovers also made it run shitty in cool weather. It ran horrible till Everyday Performance did the Qjet. Use this calculator https://uempistons.com/p-27-compression-ratio-calculator.html and seriously plug in the pistons at .040" below deck, it will give close to the actual compression. There is a member on ClassicOlds, Fun71 who used those pistons thinking he would have 9.5 to 1. He actually ended up with 8.8 to 1 compression, not terrible but not what he wanted. The .011" shim gaskets will help a lot but they cost almost as much as Cometic gaskets. The W30 auto cam has 216/217 duration at .050", someone posted a Supercars cam card on Classic Olds, if this the 285/287 duration cam. It is very close to my custom 214/214 .472/.472 on a 110 LSA, the Supercar cam is on a 113 LSA. Don't forget to throw in a 2000+ stall converter as well. The stock 1600 TH350 stall blows. My 70 went from 1/4 block burnouts with a 2300 flash stall 2004R that died to barely eeking the tires with a factory 1600 flash stall TH350C converter. The orginal 70 trans stalled the same. Chevy, Pontiac and Buick are not the same as an Olds V8, they like completely different timing curves. I run nearly 60 degrees part throttle on 8 to 1 motors and it really helps part throttle, that is another reason why my 9.6 to 1 Olds 350 sucked, I had the timing dialed back so much. It ran mid 14's with more in it but the 7.9 to 1 Olds 350 that ran mid 15's felt more lively around town. Even this 9 to 1 350 liked low 50's timing for response but it was a hair much causing the bucking. I dropped it to mid 40's and noticed much less part throttle response. I currently have the Mallory distributor and CDI box and have a similar curve, I may add 5 more degrees on the vacuum advance, it should help.

That is very helpful information. I will hang on to it for when I get everything built and in place. The last details are the most critical. Thank you!

 

[Oldscarnut]

You're in the right place. This forum is loaded with knowledgeable guys that don't mind helping.

It isn't uncommon in my opinion to swap an Olds 350 in a G-body. With the TH-350 a non-CCC carb and distributor, you don't need the ECM or its harness. Should be a fun car. Consider starting a build thread on here. We love them, and we love pictures!

Welcome to the site from Houston.

Best,

Jared

Thank you! Once I get the engine back from the Machine Shop I will start with the photos. I would like to send the 3.8 back to GM postage due because of the way they made decisions in the 80's. I had a 67 Mini Cooper S that has as much HP with 1/3 the engine. Stupid is as stupid does!

 

[Oldscarnut]

I think you have a solid plan.
Your main concern seems to be with wiring. Luckily, the starter is on the same side, so you can keep everything ORIGINATING from the drivers side. The ECM harness on the passenger side can go, though. Pull the inner fender, and undo the 2 screws on the grommet retention plate. Then, pull the grommet and wiring.

Thanks! I have to pull the inner fender to get the old A/C evaporator out and install the delete panel anyway. Once the 350 id built, the 3.8 takes its boat anchor role and I will have an opportunity to clean up the engine bay and do the chores. My goal is to have it on the road before Summer but that may be a little optimistic

 

[Oldscarnut]

http://everyday-performance.com/distributors.htm
the dudes over at everyday performance have a distributor service. I've bought two of their carbs and both were awesome. I bet their distributor services are just as good. I'd imagine they'd be able to set you up with a distributor, maybe even a numbers matching or at least era correct one if you don't have one, plus answer a lot of your questions. my knowledge mainly stems from HEI's, don't really know sh*t about pre hei stuff. some of the other members on here most likely do.

I made contact with them today. Thanks for the info. One great thing about living in the boondocks, there are few machine shops and gearhead businesses to choose from so getting stuff to the experts takes a load off my mind!

 

[olds307 and 403]

Everyday Performance did my 800 cfm custom tune and rebuild, including rear bushings for less than a new decent carb would cost and runs great. Are you planning on getting these pistons? http://www.supercarsunlimited.com/350-Piston-Set-d986.aspx

 

[Oldscarnut]

Everyday Performance did my 800 cfm custom tune and rebuild, including rear bushings for less than a new decent carb would cost and runs great. Are you planning on getting these pistons? http://www.supercarsunlimited.com/350-Piston-Set-d986.aspx

It is the plan right now based on the parts already bought and installed.. Weighing all the advice too, since I don't care about ET or launch, 6000 rpm or 400hp, making it run well is the priority.

 

[olds307 and 403]

Seriously consider the Mahle 10cc forged piston. Lighter, stronger, taller compression height and a 1mm/1mm/2mm ring pack. The thinner rings actually seal better with much less friction. I believe Cutlassefi(Mark Remmel) sells them pistons, rings and wrist pins for around $650, very close to the price of an inferior cast piston. He is good to deal with, I have bought multiple items off him. Good luck.

 

[Oldscarnut]

Seriously consider the Mahle 10cc forged piston. Lighter, stronger, taller compression height and a 1mm/1mm/2mm ring pack. The thinner rings actually seal better with much less friction. I believe Cutlassefi(Mark Remmel) sells them pistons, rings and wrist pins for around $650, very close to the price of an inferior cast piston. He is good to deal with, I have bought multiple items off him. Good luck.

I will do some research, and thank you