those that mean they came off a 5.3 liter truck and are they better that the 243?thanks

 

Yes, they are off a 5.3 liter Gm vehicle. They will raise the compression compared to the 243 head.

 

so there better and are they bolt on direct beause i can pick up some from a junk yard what year trucks will fit on it?thanks

 

The GM 5.3L engine is RPO LM7, which is commonly found in vehicles like Suburbans and Silverados.

 

The advantage was the ability to port them and modify the chamber. I wouldn't bother with them off a truck you are better off with 243's at a minimum.

 

Stock 5.3 heads on your LS1 will be a downgrade. Ported 5.3 heads... different story. Yeah, you will raise your compression a bit, but the heads flow significantly worse than an LS6 head, stock for stock.

 

the only reason im asking is i was on the texas speed website and saw some heads

prc 220cc 5.3 stage 2.5 cnc ported for 1,134.99 or
prc stage 1.0 ls6 cnc ported for 1,024.99

they claim both to add 50hp thanks

 

even ports 5.3s are called budget heads for a reason.

Get some good ported 243 heads, or and least the prc stage 3 heads.

is adding 50 hp is not worth putting on new heads?

 

I have a buddy of mine who has the TSP 5.3 heads on his Trans am and his car made good power. They are bad for the price

 

I made 410 rwhp 405 rwtq with my small cam and 5.3's.

 

what do you mean 50hp is not enough for swapping my stock heads with one of the aftermarket ones?

 

so you used the 5.3 heads that i listed above right and got 410hp not bad what size cam do you have?

 

Those r little better than ur stock LS1 heads but still cant compete with 243 LS6 heads. Get the LS6 ported my friend. Check speedinc.com and texas-speed.com

 

my friend they are 243 ls6 ported like i posted from texas speed.com
so those are the better ones your trying to say right

 

No these were ported by Jay from Absolute Speed who went out of business. He was one of the best porters of his time. I am using a 224/228 581/588 112lsa comp cam. Of the 2 heads you have listed above I would go with the stage 2.5 5.3's over the ls6 stage one. The 5.3's have been worked over more the stage 1 243 so they will flow better and have more compression. The 5.3 heads have shorter runners and a smaller chambers 200cc and the ls6 has a better casting with 210cc chambers. The ls6 have the potential flow better and have more room for work. If you are going for a larger cam and peak hp I would go with the ls6 stage 2.5. I believe the 5.3 are better on the street and yield a little more in the lower rpms. How much more will the ls6 flow. It all depends on the porter. For people to say well that is a truck head is absurd. I have no doubt that I could get 440-450rwhp with a bigger cam and a ported fast. But that was not my goal. I wanted more down low. Although I am considering a fast, injectors and maf in my near future.

I guess what it all comes down to is what you want to spend. If money is not an issue I would go with a set of AFR, Trick Flow, ETP or Cartek. I choose my A.S 5.3 because I had seen several people over at ls1 tech put down 430+ rwhp 5 years ago with these heads before all these other great heads came out. And I got them brand new with crane dual springs, titanium retainers, bronze guides etc for only $750.

I would start researching a talking to some vendors with what your goals are. If I could do it again, I would have just waited and saved for a supercharger.

 

spend the money on some good heads.



with a cam swap, UP pully, LTs CAI plus a tune you can get close to 80 hp

save your money get some stage 3 ( I dont like those names) or some of the better TSP, LPE or AFR205 heads, a good, but not too big cam, UP pully, CAI, TB and a tune.

Keep the lift on your cam to .600 or under saves valve spring life.

the other big question is what do you want from your vette?

some guys want big numbers, but the car still runs like a turtle off the line or out of corners.

Look at combination, heads and cam that may provide the best UNDER THE CURVE numbers or area on the dyno chart.
The HP and TQ down low the quicker the car will be off the line, out of corners and actully more street able too.

Good Luck

 

I have the PRC 220 5.3 heads on my 382 and I love them. Driveability is great, low end is awesome, and it just makes good power all around. Yeah, I would rather have some AFR's or some TFS heads, but at half the price these heads are a bargain.