Hey guys,

Pretty new to this site and to the third gen world. I have found a lot of great info on here, and now feel that it is time for me to take a dive to the deep end of the pool. I am looking to chane out my 89 305 TPI set up with a 350 and have some upgrade questions.

I picked up a 350 block casting #14093638 that has been bored .30 over dome pistons and the crank is .10 over ($60.00). No heads or cam in it. I wanted to build it up a bit but not sure where to go. I have a budget of $1000.00 and was looking at the following parts.

Heads: $100.00
991 casting W.3.3 date code. 1970-76 3998991 350cubic inch engine, 1.72 intake valve, 1.5 exhaust valve, 74.56cc chamber.

Cam: $100.00
JEGS Performance Products #555-200120
Hydraulic Flat Tappet Cam & Lifter Kit
1967-90 Chevy 396-454ci
Lift: .475"/.500"
Adv. Duration: 266°/276°
RPM Range: 1500-4000

Roller Rockers: 120.00
JEGS Performance Products #555-20111
Aluminum Roller Rocker Arms
1.5 Ratio
7/16'' Stud

I was hoping to use my current TPI set up with all of this, and just porting and polishing everything (TPI set up, intake, and the Heads). I know I have to do the standard 305-350 TPI upgrades (knock sensor, bigger injectors, new prom,etc). Im not looking for a spead deamon, just something that burns a little rubber, 300hp max maybe. The car has a 700r4 auto, and standard rear in. I will be doing 95% of all the work myself.

Any suggestions would be great.

Thanks

 

Alright well your good to go on the block, do you know how much of a dome those pistons have?

As far as those heads dont waste your money, the heads on your 305 are much better than those. I would say try to find a set of vortecs but that would require you to change your intake manifold. Try to find yourself some aluminum 113 heads, they arent the greatest heads but you'll lose 50lbs off the front of your car and they are WAY better than those 991's.

That camshaft wont work as its for big block's. If your sticking with TPI I would suggest something in the 212/218 range with 112-114lsa. I ran a COMP XE-256 on a 112lsa in my 355tpi with RHS heads and it ran good. Make sure you get springs to match whatever cam you go with.

Those rocker arm's are offset and they are for 7/16" studs. If your going to be running stock heads you will need non offset rockers for 3/8" studs.

Do some looking around in the TPI boards and see what other people are running. If you set it up right you'll have decent power and mpg.

 

ok so for cam something like this?

Comp Cams #249-SK12-262-4

Xtreme Energy™ 262H Hydraulic Flat Tappet Camshaft Small Kit
1987-1998 Computer Controlled
Lift: .464"/.470"
Duration: 262/270
RPM Range: 1500-5500

 

Also is my block still considered a 350? or is it a 355 or 383? Again very new to all of this.

 

That cam is deffinatly more along the lines of what you'll be wanting.

If your block was bored .030" over its 355ci now.

 

What do you think about these heads?

Casting number is 601. These heads do have the accessory holes. Heads fit all small block Chevrolet engines, 283 - 400. If you need them drilled for steam holes for the Chevrolet 400 we will do that for you at no extra charge. Heads have the 58 CC chambers.

 

Those are older 305 HO castings, the heads on your 305 flow better but have smaller intake valves, before you buy heads you have to figure out how much of a dome your pistons have.

I would deffinatly keep looking for a set of 113's if not atleast get the iron L98's, I believe the castings are 083's and 217's.

 

So if I go with the 113 can I use my same intake from the 305 TPI?

 

Yes.

 

Great. I found a pair on ebay, what do you think? Will I need to change the springs or just run them stock?

http://cgi.ebay.com/ebaymotors/90-Co...Q5fAccessories

 

The 638 casting block is a roller lifter type. Your TPI has roller lifters. Why do you keep listing flat tappet cams?

None of the heads you have listed so far have the same bolt pattern as your TPI base. Any particular reason you aren't considering reusing your 305 heads?

(Although hinted at already, the cylinders are bored 0.030" over, and the crank has been turned 0.010" under. The devil is in the details.)

 

I was under the impression that I could not use the 305 heads on the 350. Do they just bolt directly up, or do they require modification? As for the cam lifters, again I'm really new to all this, and I don't know what I am in need of. I have purchased a couple of books, but there seems to be an increditable amount of combinations out there. What type of cam and lifters do you recommend?

 

Okay, I'll go through some basics.

305 and 350 heads will bolt on to either block. The difference is the 305 heads have smaller chambers, so putting 305 heads on a 350 block means you need different pistons than you would need with 350 heads in order for the compression ratio to be correct. Typically 305 heads with 58cc chambers on a 350 would require pistons that have 6cc's more "dish" than the 350 pistons you would use with 350 heads. Truck 350's usually have dished pistons that fit the bill, so putting 305 heads on a truck 350 will raise compression up to passenger car levels.

BUT...

The thickness of the head gasket you use also affects compression ratio. That starts to get a little involved, because you want the distance from the top of the piston at top dead center to be 0.035"-0.040", and that can vary depending upon the pistons you use, and whether or not the block has been "decked" to clean up the head gasket sealing surface. Typically, you want to use thin head gaskets (metal shim, ~0.015" thick when compressed) with rebuild-type pistons, but again, that's something that depends upon the pistons and your block.

My apologies, I just read back over your original post and it says "dome pistons". Are you sure about that? Do you have pictures or part numbers you could post? If it really does have dome pistons, forget about using 305 heads. We really need to know what pistons it has before we talk any more about heads.

Cam - in 1987, Chevy went to roller lifters in passenger car engines. They used the same blocks in trucks, but didn't use roller lifters in those engines. I'm assuming you don't know what your engine came out of, so it would be a good idea if you could post a picture of your lifter valley, if possible. We're looking to see if the nubs in the center are machined, drilled, & tapped. If so, then it is "roller ready", and you can transfer over all your 305 lifter stuff - anti-rotation "dog bones", the "spider" retainer, push rods, and the cam retainer on the front of the block (although there were two different cam retainer plates, and your 305 plate may not be compatible with your 350 block - it's a year thing, not a 305 vs. 350 thing). All you need to buy is an aftermarket roller cam made for factory roller lifters, and a new timing set. Everything else will transfer over from your 305.

Just for the record, roller lifters are much better than flat tappet lifters.

Yes, there are a lot of different SBC combinations out there. Also in 1987, the factory went with a different intake mount bolt pattern, with the center two mount bolts on each side at 72 degrees, instead of 90 degrees like the rest of the bolts. Except in Corvettes - they had all of the bolts at 90 degrees, so those 113 heads will have all of the bolts at 90 degrees. You can elongate those bolt holes in your TPI base, but let's figure out what pistons you have before we continue to consider those 113's (which have 58cc chambers, by the way - because they are made out of aluminum).

Those Vette heads also don't have the heat cross-over passages like your 305 heads (and 350 iron heads) have, and that passage is used to get exhaust gases for the EGR valve.

 

WOW! Talk about getting a free education on this site. I greatly appreciate all the info. I will take pics tonight of the block and post them, as well as the pistions. I can tell you that the pistons look more like this:
http://www.jegs.com/webapp/wcs/store...-1&showValue=3
They really dont "dome" that is what the guy told me whom I bought the block from. They have two indentations on them, so from what I have read they are more flat top pistons.

 

Correct, there flat tops with valve releifs. Those with 113's, 083's, or 217's would keep your CR right around stock 9:5ish.

 

Ok guys, here are some pics I snapped of the motor. Not sure if you need others angles, just let me know what you think.

 

Here are a few more. The casting number was really hard to make out, but after process of elimination I got it figured out. Also the motor is stamped with the GM 5.7 logo on the right rear. Thanks again for all the advice.

 

Here is some info I found on the pistons. Looks like they come from Flatlander Racing, and they are TRW pistons. Specs:

Part #H631P-30
CID 355
Comp Ratio

58cc-10.41
60.5cc-10.11
64cc-9.73
68cc-9.33
72cc-8.97
76cc-8.63
Comp. Dist-1.560
Piston Shape-F/T
Price/Each-$28.00

 

If you look at the sides of the block, you'll probably see "638" cast in large digits there.

That is certainly a roller-ready block. You even got the "spider" retainer.

 

Ok so if i go with a roller cam, what duration should I be looking for? And will the 305 heads bolt right up? Based on the specs I got for the pistons, if I put the 305 heads on then I m going to be at 10.4 compression. Is this ok?

 

58cc heads would probably give you higher compression than you want to live with on the street, unless they are aluminum. 64cc iron heads should be fine.

The "Comp. Dist" of 1.560 means the crown of the piston should be level with the block head sealing surface. Check to be sure. Most likely a .035"-.040" compressed thickness head gasket will be just right.

 

know this tread is old but ive been trying to find out what those numbers ment forever. so the guy i bought my long block from WASNT lying about it having a roller cam. thirdgen is gold..

 

I wouldn't go that far. 638 blocks were fitted with both roller and flat tappet lifters from the factory. And, you can "regress"-fit flat tappets & cam in an engine that originally had roller lifters.

 

LMAO oh well back to the drawing board. when i bought the motor, he had pulled the intake off to show me the roller cam but i didnt know how to identify such a thing then (still kinda dont). i was just hoping i had an ok setup so id know where to go. searching for vortec heads on craigslist in another tab as we speak..well, type anyway. but the motor came from a 92 caprice so that added to my roller hopes with fingers crossed