305 tpi on 350 short block

[Footjoy]

Will a 305 tpi unit with heads work on 350 block?

[andrewb70]

Will a 305 tpi unit with heads work on 350 block?

Define "work."

Andrew

[Samckitt]

Physically the only difference between the two systems is the size of the fuel injectors & the end of the fuel lines of the intake are configured a little different. The 305 fuel lines come out towards the front of the car & turn downward, the 350 ones are more straight. You can either change injectors or up the fuel pressure to get more fuel flow. I have done it, it will work.

[Footjoy]

Scott will the heads be ok or will compression be to high?

[TPI Monte SS]

If you have stock cast 11cc dished pistons in that 350, with the 58cc 305 heads you'll be up around 9.7 or 9.8:1. Doable on pump gas, but you'll need to change the injectors and chip to get it to run right. Run it lean with that compression and you'll probably have trouble.

[EFI69Cam]

The stock TPI was designed to feed a 305. On a 350 it noses over at 4500 RPM. Fine for a truck motor, but not really a performance choice.
You will be wanting larger runners, base and TB after awhile.

[Samckitt]

Footjoy - Not sure what the chamber size is of the 305 TPI heads. For soeme reason I have 67cc in my head.

[Footjoy]

Well i think I will keep looking could of bought 305 but really want 350. Another question, outside of alum heads is there a downside to cast head LT1, like out of cadilac? Thanks for the help

[Samckitt]

Make sure you check the cast liter size on the back of the block of the iron head LT look alike engines. It could be an L99, which is 4.3 liters & 4.3L will be cast in the block.

[Footjoy]

Scot What horse power does a 5.7 cast iron head LT1 put out?

[Samckitt]

Seems like I read that it made around 275 range. Not 100% sure. I'll try to find some numbers on the net.

[TPI Monte SS]

The iron-head LT1 (Caprice, Caddy, Impala SS) made 260 hp and 330 ft/lbs. The F-body aluminum-head motor made 275 hp, and slightly less tq. than the iron LT1.

[Footjoy]

What would it take to get 350 hp out of lt1? or should I start a new thread?

[TPI Monte SS]

A cam swap, some headwork, headers, and a tune should get you 350hp easily.

[Boulder69]

What would it take to get 350 hp out of lt1? or should I start a new thread?

Save your cash and buy an LS1. They make 350hp stock and don't have an optispark distributor. The iron block LS-based truck motors are another option you should look at.

[MonzaRacer]

Nothing worng with The LT1 just swap in the Delteq dis swap or maybe a megasquirtnspark. I believe even MSD has a plug in set up to use the sensors of the optispark. I have heard of peeople even removing the cap on optispark and someone made a cool crome one and jsut used it for the sensors inside.
And isnt LT1 reverse cooling and you have to have complete longblock?