I am going to swap out my 305 tpi for a 400 carb. plans to go FI later once i get some more green but my question is. the 400 is stock with the exception of a double rolling timing chain and a RV cam (not sure what he ment by RV cam.) but a rough guess of how much HP and torque the motor would produce would be much appreciated,also if any of the more experianced handfs have some tips to give me some more power for later upgrades it would be appreciated. i do have it in mind to get rid of the carb and go fduel injected with in a year. my guess is that the motor will pull at least around 350 hp so would 25 lb injectors suffice? or should i go larger? another question is how much psi would the motor with stand with out having to contantly worry about damaging the motor if i decide to supercharge? Cam suggestions would be nice to, but please note that this WILL be a daily driver. i am not looking for a gas saver if i was then i wouldn't be putting the 400 into the f-body, but i don't want a gas hog i am figuring right now about 10 mpg so not much lower than that.

 

"RV cam" is code for "inexpensive replacement cam". They tend to have low duration and lift, produce good idle and vacuum.

It probably has in the range of 250-275 HP, depending upon what exhaust you're using. And that's "gross flywheel" HP, not the "net flywheel" HP rating used to come up with the 205 HP for your 305.

The engine is limited by low compression and horrible heads. You can improve that considerably by using better heads. Even the heads on your 305 right now would be better.

I'm not sure I'd do this in two steps. I think I'd get the funds together to do the EFI when the engine goes in to avoid the costs associated with temporarily going carb that won't be of any use to you with EFI.

What EFI system were you thinking of using? You can make a lot of difference in how the engine runs, as well as the power it puts out, by choosing heads, cam, and EFI that will work well together.

 

if you are thinking about a supercharged or turbo 400 you should wait until you can do it in one shot. you will be changing them pistons for sure

 

Is it a factory 2 bolt main block or a 4 bolt? I heard 2 bolt 400's are better but not sure how much power i'd want to put thru one of those under boost. With good heads/cam/intake, it wont take much pressure to start creating a good deal of power. May not be that safe on a factory block.

 

Absolutely a 2-Bolt 400 with splayed caps is stronger than the factory 4-bolt because of the locations of the factory bolts the block is very thin where the stock location is the splayed cap is angled into a thicker part of the block and actually has to be sealed cuz it enters a water jacket, you can make more horsepower than you'll ever want on the street without a turbo or super charger.

 

The intake i plan to use is this not sure it will bolt up to my 400 but thats why i am posting to the forums. I plan to use this throttle body with it.

As for the heads i am going to go with these the only thing i am unsure of is what chamber size to get.

I haven't the slightest clue as to what type of cam i would swap out, as i know nothing about cams.

 

Thats an LS1 style intake which will not work with the small block chevy. So thats out of the picture.

the Iron eagle heads are ok heads, but you may find a better deal on pricing at other places than TPIS. 1150 for iron heads seems high, as you can have aluminum heads that flow better for same price or just a tad more.

 

That's an LS1 intake. Won't fit a Gen I 400.