Intake Manifold Question.

[c1500deathtrap]

Hi guys. new to the forums. liking some of the post i have read so far. i do have a question i hope someone can answer.

the motor in my 94 finally kicked the bucket. I am in the process of rebuilding a .030 350 to replace the tired 350 currently in it. the block im using is out of a 70 Nova, and i will be using a set of 217 heads i have that are in nice shape. they are iron and center bolt, but have the old style pre 87 intake bolt pattern with the 2 center ones being different. i have a oldschool edelbrock performer intake sitting on the shelf i can use with the heads. I also have found an adapter plate to convert 4 barrel intake to TBI.

Has anyone ever done this? i know it would need some modifications for vacuum lines and such which im not too worried about. the manifold doesnt have EGR so would i need to get my computer flashed or will it still run ok with the light on? im more used to working on carbed vehicles. My other vehicle is a 73 Nova.

any input is appreciated!

btw i have already upgraded the fuel pump to a 255lph 17psi External in line pump.

Stock TBI intake should bolt to those 217s. Those are marine heads very similar to the 083 TPI 350 heads.

Look what i found https://www.hotrod.com/articles/hrd...-tbi-heads-on-a-carbureted-1970s-short-block/

 

[c1500deathtrap]

If you're putting A tbi manifold on old heads, oversize the center 2 bolt holes and put a big washer under that bolt.Or weld it up/ plug it and drill a proper hole. That is if you want to keep emmisions.

 

[c1500deathtrap]

Stock TBI intake should bolt to those 217s. Those are marine heads very similar to the 083 TPI 350 heads.

No, the center two bolt holes will need to be modified.

 

[xx94Z71xx]

yes deathrap is right the center bolts holes will have to be modified. Those heads are an oddity they have centerbolt valve covers but pre 86 bolt intake bolt pattern. is this because they are marine heads? i picked them up used at a swap meet. i got the valves out now, and going take them into work and check for warping on a surface plate. plan on running them as is after new seals and a quick lapping. and luckily they do have the 3 bolt pattern for the accesories so my serp belt should be ok. Im in NY but since its pre 1996 it doesnt need to be hooked to a computer so i dont need emissions. Im running .030 Flat tops so hopefully my compression isnt too high lol.

 

[xx94Z71xx]

I don't have words for this.

me niether. Chevy TBI is the most simple, reliable, and cheapest throttle body injection out there IMO. i plan on trying to keep TBI but if all else fails ill convert to HEI and Edelbrock 600 i have sitting here not being used.

 

[xx94Z71xx]

Also, flywheels will need to be swapped, the older 70 2 piece flywheel bolt pattern is different than your one piece rear main seal bolt pattern.

what flywheel should i look at using? modify the original?!

 

[Schurkey]

what flywheel should i look at using? modify the original?!

You won't modify the original.

Pick up a flexplate for an older two-piece rear main seal engine (Neutral balance) and you're good to go. There's two sizes, pick the one (153- or 168-tooth flexplate) that works with the starter motor you have

 

[L31MaxExpress]

I have a huge text-and-photo document (17 pages) about rebuilding a Vortec short-block, then converting my K1500 to aftermarket heads and a ZZ4-style intake manifold, while retaining all the emissions controls. I'll post it after I get the length cut down. I'm not good at editing my own writing.

It's do-able, but not fun.

Keeping the stock EGR valve is the worst part. I had to fabricate an adapter to go onto a purchased adapter that allows the OEM

No, the center two bolt holes will need to be modified.

Must be more than one set of 217s out there. The ones I have had myself had the TBI bolt angles. It was an older 300 HP GM 350 HO crate engine.

 

[xx94Z71xx]

oh ok i probably have an older flexplate sitting around here somewhere. if not ill grab a new one. right now just waiting on my connecting rods to come in so i can continue putting it together!

and i remember reading when i first got these heads that they are the same as the L98 heads that came on the corvettes but just iron instead of aluminum. they also came in crate motors and they could have either or for the center bolts.

all else fails i got a set of 487 heads that came out a running chevelle that needs valve seals.

 

[MarkZ28]

Tbi may be simpke and cheap, but for performance, it really shows that it's cheap. Port injection has proven to be reliable on many other cars/trucks, GM had many that were great.
Ifvyou go with an Edelbrock, get a heat shield or insulator that goes between the carb and intake. They are a good carb but heat soak like a ****. Every one Ive had, Ive had to use a heat shield of some type to prevent vapor lock and boiling over once the engine was turned off. The fuel boils and pukes out the vents, dumping fuel into the intake flooding it. Have to crank the engine over with the pedal floored a bit to clear it out