stock 1987 r10 305 build up on budget

[NCSTRONGMAN]

New member here with some questions. Im doing some budget top end upgrades to my truck.I bought it from family member before they passed recently. No im not dropping in a 350. I have bought a a set of stainless long headers, a lunati cam260/454 that should duit a upgraded head set.Im a bit confused on head choice as 87 was the year of changes,,,wht they were im not so sure.I have a 350 tbi on it now.I have a set of pro comp head with2.02/1,60 valves but told valves can only be 1.94/1.50 with stock bottom end...or could head gasket the tweaks to allow for them ? Need some exp advice on this subject - then there is likely going to be a conversation about the tbi getting an upgrade (bigger injectors? bored tbi ?)

 

[74 Shortbed]

Welcome to the site, good luck on the project. BTW, I wouldn't put a 350 in it either..

 

[1987 GMC Jimmy]

I'm not gonna tell you to ditch the LO3 because you've got your mind made up. A well-built 305 will do fine, but you're traversing a road less taken with a built 305 TBI. People build up 350/383 TBIs, and people build up the L69 HO 305s and the truck version, which are pre-86 motors, but I've never heard of the TBI version being invested in like that. Anyways, I've never heard of the thing about 2.02 heads. I've heard of plenty of people porting the pre-TBI 416/601 factory casting 305 heads to those specs. On the TBI setup, I'd talk to people in the industry to see what they recommend. Maybe SPR Performance could tell you what they setup they've done on a performance 305 TBI.

 

[Honky Kong jr]

I'm not gonna tell you to ditch the LO3 because you've got your mind made up. A well-built 305 will do fine, but you're traversing a road less taken with a built 305 TBI. People build up 350/383 TBIs, and people build up the L69 HO 305s and the truck version, which are pre-86 motors, but I've never heard of the TBI version being invested in like that. Anyways, I've never heard of the thing about 2.02 heads. I've heard of plenty of people porting the pre-TBI 416/601 factory casting 305 heads to those specs. On the TBI setup, I'd talk to people in the industry to see what they recommend. Maybe SPR Performance could tell you what they setup they've done on a performance 305 TBI.

It is probably a valve to piston clearance thing....damn it Jesse I was trying to stay out of this one. Lol

 

[Honky Kong jr]

Welcome to the site, good luck on the project. BTW, I wouldn't put a 350 in it either..

BIG BLOCK!!!!

 

[OkieFishMan]

BIG BLOCK!!!!

You are in true form tonight @Honky Kong jr !!!!!

 

[OkieFishMan]

BIG BLOCK!!!!

But I agree, BIG BLOCK!!!!!

 

[Honky Kong jr]

You are in true form tonight @Honky Kong jr !!!!!

I see 305 and yea......

 

[1987 GMC Jimmy]

It is probably a valve to piston clearance thing....damn it Jesse I was trying to stay out of this one. Lol

I gotcha. I still see all kinds of write-ups where people port the factory heads to those specs, and valve clearance issues were never mentioned. I can't say definitively, though. Ha, I guess you are in just about every thread, but that's not a bad thing.

 

[Honky Kong jr]

Depending on chamber size shrouding the valves can be an issue too. Not good for any kind of performance.

 

[74 Shortbed]

BIG BLOCK!!!!

Of course, didn't want to scare away right off the bat though, lol...

 

[NCSTRONGMAN]

Thanks - It is a valve to piston clearance issue, although there are some tricks that supposedly get you around this issue.Im not looking for a drag truck just looking to add a 100hp to make is more fun to drive and have a good sound.
I have a few emails sent out and seeing a guy today whom has a good rep.

 

[fussfeld]

Will the heads with the 2.02/1.60 valves even work on a 305's bores?

 

[4WDKC]

The reason everyone says go to a 350 is because of the bore size limits the cylinder head choices as you are finding out and if something should happen to the 305 those heads will severely limit the capability of a 350 should you swap one in. Then you only choice is to either run the 350 with these heads or try to sell them to someone doing the same thing you are doing now. Why not just drive the 305 while building a 350?

If you must hop up the 305 do it cheaply, find a set of 305 TPI heads, a cam and you will need to tune the ecm for it to be correct.

The reason you cant use 2.02/1.60 valves is the 305 has a bore that measures 3.736 inches, the 2.02/1.60 valves would physically be 3.62 leaving a mere .11 to allow air to flow around the valves and into the cylinder assuming there is no carbon build up at the top of the bore. The .11 is about the thickness of a 1/4" washers, then it has to be divided in two leaving .055 clearance between the valve head and cylinder wall.

 

[NCSTRONGMAN]

2.02/1.6 valves wont work. I talked to a local expert, he speclaizes in LS swaps.
He said with my bottom end he would find a pair of 96+ vortec truck heads w/1.95/1.5 valves, replace edlbrock performer, add conversion plate for my tbi intakeand mylunati voodoo cam would be fine..and i already have stainless long tube headers....i would need to get chipped flashed and delete egr...waiting tofind the head and buy the intake then hopefully it will being...If i blow it up down the road no moremessing will just transplant a new engine 350 or stroker with upgrade trans...i may consider ls swap after what i seen he has done!