350 Crate Motors

[tdangle]

Does anyone know if the horsepower rating is gross or net as advertised? The factory rating of my 70 350 is 255 gross and I'm trying to compare power ratings. The one I'm looking at I see rated at 190 but with 4bbl and headers suppose to be about 260.

[TJ's Chevy]

260 hp gross

[TwoFiftyShifter]

That Goodwrench 350 is essentially the same that would come in a truck from the 70s. It's an direct replacement.

[PDW HOTRODS]

In 1972 I think is when the horse power ratings changed. The same motor would have a lower rated power after the change because of how they rated them.

[Hayden Buck]

I have a 84 small block that has around 300 hp with
a 1/2 axle do I need to run it up to a 3/4 ton?
Posted via Mobile Device

[Coley]

According to some information I have found...there was a slight downturn in power in '71 from 1970.
It seems the compression ratios on the trucks up to/thru 1970 were 9:1 and in '71 they changed something (piston?) to bring that down to 8.5:1.
This change also seemed to coincide with the year (1971) that they started using a different rating system for hp so its hard to get a true apples to apples comparison.
So in 1970 you have a hp rating system that shows 255 gross hp with a 9:0 compression ratio....then in 1971 (and on) you have a re-rated (now net) 175 hp engine with a 8.5:1 compression ratio.
Regardless that new crate motor will undoubtedly provide more power than any older motor that is now probably down on compression.

All good
Coley

[Hayden Buck]

Mine has compression of 11.3 it's a 350 bored over to a 355
Posted via Mobile Device

[Coley]

Originally Posted by Hayden Buck

Mine has compression of 11.3 it's a 350 bored over to a 355
Posted via Mobile Device

11.3 compression?
....what fuel do you run in that......and where are you buying your fuel at?

I didn't think today's premium fuel (91 octane) would run that kind of compression.

C.

[Hayden Buck]

Originally Posted by Coley

11.3 compression?
....what fuel do you run in that......and where are you buying your fuel at?

I didn't think today's premium fuel (91 octane) would run that kind of compression.

C.

I get my fuel at Philips 66 and get the 91 then I dump two bottles of octane booster into the tank
Posted via Mobile Device

[garyd1961]

Originally Posted by Hayden Buck

I get my fuel at Philips 66 and get the 91 then I dump two bottles of octane booster into the tank
Posted via Mobile Device

I am normally pretty laid back but dude I don't believe nothing you say. You keep bragging about this truck you built from the ground up but nothing you say makes any sense, 350 hp running in the 10s with the motor cutting out, 11.3 compression on pump gas with iron camel humps. you say you built this truck but you obviously know nothing about high performance motors.
I think you need to put up or get out. Lets see this truck, lets see you with this truck and a up to date news paper.

[Hayden Buck]

I said I mostly built the truck my dad did the motor and trans. I can't get any pics to go on this page. I'm only a high schooler and I was asking for info not cridusim. If I'm not welcome to ask questions and answer them i will just leave and u won't here from me again.
Posted via Mobile Device

[Hayden Buck]

If you want to see pics go to the thread drag racing
Posted via Mobile Device

[garyd1961]

Originally Posted by tdangle

Does anyone know if the horsepower rating is gross or net as advertised? The factory rating of my 70 350 is 255 gross and I'm trying to compare power ratings. The one I'm looking at I see rated at 190 but with 4bbl and headers suppose to be about 260.

You need to know where the horsepower and especially the torque is at on the rpm scale. If all the hp is at 5000 rpm it's not any good for a heavy pickup.
What you need is low end torque, don't let the hp ratings fool you into buying a motor that has no low end torque.