hey im pretty new to the board, and im loving my 92 'maro drop top. have had it for about a year or so. im doing a build up project on the old 305 tbi. the engine only has about 90k on it and i just bought the tes system from edelbrock, cast iron vortec heads, comp cams xe262h, gm tbi aluminum intake manifold, and i know holley sells a tbi 670 cfm but dont know about that....so thats what im kinda doing right now, o and i just bought a new convertible top from topsonline.com....any comments on what i should do and dont want to hear just swap it with a 350.... when a 305 is a perfectly good engine to work on and build up

 

i also have a L03 in a RS. the 305 is a fantasic engine. great gas millage some power combined with very long life. you have the right idea, stock L03 exhuast is really a joke. 2-1/4 inch pipes? what was GM thinking, 2-1/4 inch is hardly adaquate for any V8. that's on my shopping list as well or i'm also considering a L69 exhuast(3" stock 305HO Z28 exhuast). i already have a set of L69 exhuast manifolds, and a L69 3" cat. all i need is the Y pipe and a 3" catback. its a hard call, i could have 3" system much cheaper but i would also like headers, at any rate stock L03 exhuast is pure crap. you are also right about the cam, its quite weak. the rear end gear could also use improvement, however your gas millage will suffer if you change these out. i would just be happy to get the same ratio but in limited slip, i dont like the open differental. cast iron vortec heads will also work great. i want to keep the mods to my car at a level where i still can run the 87 octane and maintain some fuel millage, at 3 bucks a gallon it aint cheap anymore. i would also consider underdrive pulleys. you will pick some power and gain fuel millage. holley does have a 670 cfm system and it will work with your stock wirring and computer, i believe. dont believe what most people will tell you. the 305 is a great engine, used in many cars, trucks, and vans. it had to be good to be used in so many different applications.

 

yeah i was looking at aluminum pulleys 3 piece set....jegs sells it for 159.99 kinda exspensive but meh...still looking also i have read that i can use a carb manifold like a performer rpm if i use a tbi adapter plate

 

Laptop, Moates Burn 1 and the EBL will be your best friends with the mods you have in mind.

 

i have a question about a manifold, if i want to stay tbi and have vortec heads (cast iron 64cc combustion chamber, 1.94/1.5'' valves max cam lift .475) what would be the best manifold to use? was going to probably use the stock gm 454 tbi unit. i know gm makes a vortec manifold but its pretty expensive in the 350 dollar range from jegs and i am also going to use a bigger cam from comp cams xe262h or 268 havent decided...what should i do?

 

Just use a carb intake and a TBI adapter plate, keep in mind that hood clearance will be a problem with some high rise designs like the performer RPM.

Like fast mentioned you will be very disapointed when your 1000$ worth of parts won't even make it out of the driveway. When changing as many things as you want to change DIY tuning is the ONLY way to go.

 

ya i was thinking of the hood clearence when i mentioned that...i know im also getting a tune with the mods im getting, what would be a good carb intake?

 

wow good stuff i had the exact same plans as you. i already got the headers... but im dropping in a 350 anyways. b/c its free lol

 

sweet