are the heads angle or straight plugged? Thanks - Roger

 

Straight I think. Most factory heads are straight.

 

1987 LG4 heads would be 081 or 187 castings. BOTH are straight plug heads.

 

Thanks. - Roger

 

are these heads any better than lo3 heads?

 

Yes

 

can i take a set of these heads and have them bolt right onto my tbi setup on my lo3 without a problem?

 

MANY of the LG4s have 187 head castings, that is the SAME casting as the TBI 305.

Define "BETTER"

They do flow a little better on the intake side, but lose just as much on the exhaust.

You go from 175 CFM intake on the TBI heads to 195 CFM intake on the TPI heads. But you go from the 135 CFM exhaust to about 105 CFM on the TPIs.

You also lose the "FAST" burn capability which necessitates more timing advance for peak HP. More timing advance starts the air/fuel mixture burning sooner. That means the pressure from combustion is actually fighting the pistons still upward movement for about 6* farther with the TPI heads than the TBI heads. When the total window is about 50*, 6* is alot of the time and alot more negative work on the crankshaft. Going on 28* BTDC total advance for the TBI heads, 36* BTDC total advance for the TPI heads, and peak cylinder pressure about 15* ATDC.

The end result is you end up trading ALOT of low-mid range torque and take a terrible hit on gas mileage for a little more power over 4,500 rpm. (I took Dewey's PORTED 416s 4,200 rpm to rise to the level of the STOCK 187 TBI heads and start pulling ahead on his CAMMED 305).

Spend your time and money working on the Exhaust, Chip, and tiny camshaft(1.6:1 rockers at the minimum).

 

i did not know that, i thought they always had 416's.

 

NOPE, 1987 introduced the center-bolt valve cover heads, 081 and 187. I think I have seen more 1987-1988 LG4s with 187s than I have with 081s. Keep in mind that the LG4 was also used in 1988 in the Caprice and Monte Carlo.

 

so are these 87 305 carb heads any better than my 89 305 tbi heads?

 

Did you read Fast355's post at all?

They very well might be the same head casting. What # are they?

That's kinda a loaded question, everyone on these boards like the 416/081 castings, except Fast355, and about 3 other people on the TBI board.
The ramp in the intake limits flow at the upper RPM limit. The TBI heads are better for low RPM (there, i'll give ya that one..), and the heads without the ramp (416's, 081's, 601's etc etc) are better for higher RPM.
What do you have and what do you want?

 

Stock for Stock, NO

Ported and Ported, DEPENDS on the application

What cam do you have?

Chip Burning?

Exhaust?

Intake setup?

Transmission setup?

Rear-end gearing?

What are you planning to use the car for? Daily Driver, Street-Strip, Drag, Road Race, Autocross?