hi im pretty new , but if you've read any of my post you would know im having a 1970 gto 406 engine built(local shop)..it in the sig..anywaz heres case..the whole 406 package is gonna run me about $3,000.00 with engine being built wiring harness new motor mount ,and the tech said that the 406 should put out 460-480 hp..and he asked me where the engine is that came in it stock ..he wanted to know because he could put all the easy bolt ons(Holley 750 cfm carb,March pulleys,k & N) and a 144 holley power charger w/manifold on the original L98 and save me about $1,000.00..and make about the same hp..is this about right or is he just tryin to do this project the easy way?..any input would be appreciated! one other ill be driven next summer instead of next winter if i go with the holley power chager.

Well, you got me confused.

You want to build a 406? fuel injected? blown? what about an L98?

sorry for the confusion..as for the L98 convert to a carbed engine and throw a 144 holley powercharger on it..+the bolt ons

the 406 is n/a but has an entire forged bottom end, dart heads, super victor manifold etc...its in the sig

but if you've read any of my post you would know im having a 1970 gto 406 engine built

A 400 pontiac motor ar a 400 sb chevy motor. they are major league different!

A 400 Pontiac Engine will provide more torque than a SB 400, well assuming they are built with non exotic high dollar parts. Otherwise, the time and inclination and money it would take to put that BOP block in the compartment would probably cost nearly as much as a stout built Chevy 406 with high dollar parts.
Of course no matter what you do it is still impressive to see someone to go though with the project. Of course the best bang for the buck would be a rebuild of the L98 and Supercharging it!

Decisions , decisions, both sound really cool though !

ok ill be more specific the engine was in a 70 gto when it was pulled , it originally came out of a upper 70's chevy truck

-what about the hp quote from the shop tech..460-480 sound bout right?

-questimates on the blown L98 would be appreciated too.

BOP block??

Buick, Olds, Pontiac. BOP used a different bolt pattern then the SBC (Small Block Chevy).

no one has an idea about the hp range??

How about this guesstimate?

425 Hp 430 ft lbs

is this guestimate off personal expierence or pullin it out of the air?

well I seen claims of na 406ci motors doing it, chatting with people at the strip. It would be possible for a 406 as long as the right parts are used.

For a 350, like my ZZ3, chances are very slim unless its rammed with a blower. stroker kit, etc.

It really depends on what is inside the 406. what cam, what heads, port work what size carb, what exhaust.

You can have a 200hp 406 or a 700 hp 406 with just changin those variables.

I have a 406 in my formula but a fuel injected one. a lot of fun.

Another variable you did not mention is whterh or not it will run on pump gas? I am assume you are going to run 93 octane which wil limit your comression to about 10.5:1 with aluminum heads. If you are using cast iron heads, figure 9.5:1 compression.

If the heads are out the box and a relatively mild cam is used, you can expect somehwere around 350-375 HP. a little port work and a bigger cam will net you closer to 400HP.

Keep in mind when you are selecting a cam for a 406, the motor will see the cam as smaller than it really is. That is, you can get away with a larger cam without sacrificing drivablilty. Also 406's make a lot of torque, is your suspension set up to handle it?

I run a 406 with a 700r4 and 4.11 gears. Getting the car to hook up was quite a challenge.

This was an easy choice for me. No replacement for displacement. I chose the 406 with a possible supercharge. I dont need all kinds of figures to figure what I would choose since all those other things are changeable and need to be either way on a different engine. You wouldnt put a L98 cam in a 406 would you?

no ...no way ..not puttin no l98 cam in the 400....wouldt be worth the trouble.

fast bird:
my specs on the 400 on my sig
what kinda hp are you gettin on youre 400?

what i relly wanna know is that

am i better off building off my stock L98 (hellavalotcheaper)

-mild cam/rockers
-dart/world heads
-holley carb 650 on the L98 prolly
-headers,ehaust..etc.
-k & n
...144 holley power charger would come later.

or buying the 400 block and building it from scratch.


i pretty much just a 400 hp engine..does anyone here even have 400 hp L98 n/a or not..with stock crank,pistons and rods
i dont really mess with the internals if i go with the L98

I REALLY HATE TAKEN THE ENGINE IN AND OUT!

ps
nothing is paid for right now so im not married to any set up right now.thankxx for any help...cuz i need it.

I am pushing about 525 HP at the crank out of my 406, but HP = $$$

How fast do you want to go? That will dictate which motor you will build. Also, do you have to worry about inspection?

Truth be told, once you get to upper HP in a 400 block, cracking the block becomes a major reality.

If you are looking to run with the LS1 crowd at 12.9-13.0, it can be done with an L98 if done properly.

If you have more questions, feel free to e-mail me. Believe me, I was in your exact dilemma a few years ago.

no ...no way ..not puttin no l98 cam in the 400....wouldt be worth the trouble.

fast bird:
my specs on the 400 on my sig
what kinda hp are you gettin on youre 400?

what i relly wanna know is that

am i better off building off my stock L98 (hellavalotcheaper)

-mild cam/rockers
-dart/world heads
-holley carb 650 on the L98 prolly
-headers,ehaust..etc.
-k & n
...144 holley power charger would come later.

or buying the 400 block and building it from scratch.


i pretty much just a 400 hp engine..does anyone here even have 400 hp L98 n/a or not..with stock crank,pistons and rods
i dont really mess with the internals if i go with the L98

I REALLY HATE TAKEN THE ENGINE IN AND OUT!

ps
nothing is paid for right now so im not married to any set up right now.thankxx for any help...cuz i need it.

Exactly. How fast or how much money do you have to blow. Those 2 things will determine what you will build and how good you will build it.

id like to run around low 12'shigh 11's on motor ..and i got $4,300.00 to spend on motor..with that some one told i should buy a 385 fast burn crate (zz4)...im thinkin that is a easier way to go about it.