Whats the most HP I can expect to get from my 305 TPI car?
Also, what is everyone getting with their TPI 305 cars in MPG on the highway?
I am considering my build options and everyone is telling me to keep my car with the 305 TPI setup. My other option is to go with 400 small block and carb setup, which would pretty much turn my car into a non-daily driver.
Just wondering how my Iroc will hold up with a mild built 305 TPI setup against the 5.0 Mustangs these days?

 

Depends on what you consider mild. The 305 is a good motor. Its not a 350, but its a good motor. It will hang with close to stock 5.0 mustangs stoplight to stoplight, but once you get to a track........Go 400ci with a stealthram or LT1 intake. If F bodies were meant to be carbed, they wouldnt have started fuel injecting them ;P

 

My friends are telling me that my car would not hold up to the 400ci motor I have built without basically building a new subframe system underneath the car. My car is a T-top version and they say its weaker and will twist up very easily. I am also being told that if I stick with the 305 TBI setup I can get around 25 mpg with the car. Is that true or what would be closer to the actual MPG I could expect? If the milage will be close to that range then I am leaning towards the 305 TBI build so I can use the car as my daily driver.

 

I'm hoping when you say TBI you really mean TPI. 400ci is getting to where you MIGHT want to start thinking about beefing up the subframe connectors. The 400ci motor I would expect to get about 12-15 mpg. The 305 woould be closer to mid 20's.

 

Yes, sorry I meant TPI. After much thought, I have decided on using my 400 engine with the Weiand/Holley Stealth Ram setup and LT1 52 mm throttle body.
Not sure on what all else I will need to complete this build from that point.
I would appreciate any and all suggestions/ advice on how to finish my build from this point.
I guess I am planning to keep the 700R4 tranny also. Would my 86 Iroc need a stall in it since my engine is already going to generate lots of low end torque? Not sure on what gears it has right now, I think they are stock.
My exhaust is already bought. Edelbrock headers, 2.5" lead pipes into 4" main pipe back to Hooker Performance muffler with dual outlet 2.5" tail pipes. No CAT. since my state right now has no inspections. Offroad Use Only...

 

Here is my 400 sbc build right now as it sits. I do not plan on changing anything on this engine except for the intake/cam/lifters to go to the TPI setup with the Stealth Ram setup.
12:1 100cc dome pistons, standard 4.125" bore, Chevy 350 Rods/arp rod bolts, 76 cc chamber heads, rebuilt with big valves, heavy springs, roller tip steel rockers, hardened pushrods, Perfect circle plasma moly rings, Clevite 77 rod/main bearings, melling high volume oil pump, Air Gap Alum. dual plane intake, Holley 750 dbl. pumper dual line carb, B&M 2500 stall converter and built Turbo 350 auto tranny.
Summit K1107 cam-Advertised Duration 292/302, Lift .488/.510 114 deg. lobe separation 3,000 to 6,500 rpm operating range

 

You could go a bit more lift on the cam, especially on the intake side. Your compression is a bit high too.....what kinda gas are you going to be running?

 

I picked the cam profile for its 114 deg. lobe separation. Hoping that will help me bleed off a little compression also. I calculated out my compression to be around 10:4 or 10:5 to 1. Also used thick head gaskets. Killed my quench ratio but there is just no other way right now.
We ran the engine for its break in with good name brand 93 octane and it seemed to do OK with carb intake.
Due to my limited funds to get all the TPI stuff for this bigger engine right now I am going to have to just stick with its Holley 750 Carb setup for now and try to get it going with that.
Later on, as funds get built up, I still want to convert this engine over to TPI. Probably end up going 30 over with flattops when that time comes though.

 

what timing cover did u use the 400 timing cover or the 305 cover with the stock balancer