Silly question for the TBI-Vortec HR folks?

[n2xlr8n]

Hi folks!

I'm hoping there is a simple resolution to this, but...

Based on an article (OnAllCylinders, Jeff Smith) on converting a post 85 SBC block to hyd roller, I purchased the parts.
Then, I join the forum and read that at least some of these non-roller blocks weren't drilled/tapped. My original V0930TPA engine is in fantastic shape, and I have no plans to pull it and build it; I simply wanted to upgrade to Vortec heads, HR, HEI and a Holley.

Any advice on the Spider retainer bolt pitch and length?

Worst case: Let's say the bosses aren't even on this block- can I simply use old school 350 SOLID roller lifters with a tie-bar? I know cam grinders hate this idea, but I'm not racing and it's a tiny 208/214 .450/.450 lift camshaft.

Thanks for the input!

 

[Schurkey]

You'd want a block that has the bosses for the spider hold-down bolts. Even if you had to drill 'n' tap yourself, at least the bosses are there.

Also needs the holes drilled and tapped in the front of the block for the roller-cam thrust plate. The small-blocks have two part numbers for thrust plates, one has a wider bolt spacing than the other. I don't know which blocks got the wide thrust plate, and which got the narrow thrust plate.

You need the roller-cam-compatible timing set. You can get the chain, both sprockets, and the thrust plates 'n' hardware by buying the GM timing set.
www.summitracing.com/parts/nal-12371043

Chevrolet Performance 12371043 Chevrolet Performance Timing Chain Sets | Summit Racing

Free Shipping - Chevrolet Performance Timing Chain Sets with qualifying orders of $109. Shop Timing Chain and Gear Sets at Summit Racing.

www.summitracing.com

BEWARE, there's some evidence that certain blocks have the lifter bores sabotaged by counter-boring the upper part to a larger diameter. The roller lifters hemorrhage oil when the cam lobe pushes the lifter up. Check your lifter bores!

If you insist on putting Vortec heads on the TBI block, you'll want to drill one hole in the head gasket surface of each head, to allow coolant bypass on the right block deck. The other head is drilled "just because" someday you might have the engine apart, and swap heads from left to right.

 

[n2xlr8n]

You'd want a block that has the bosses for the spider hold-down bolts. Even if you had to drill 'n' tap yourself, at least the bosses are there.

Also needs the holes drilled and tapped in the front of the block for the roller-cam thrust plate. The small-blocks have two part numbers for thrust plates, one has a wider bolt spacing than the other. I don't know which blocks got the wide thrust plate, and which got the narrow thrust plate.

You need the roller-cam-compatible timing set. You can get the chain, both sprockets, and the thrust plates 'n' hardware by buying the GM timing set.
www.summitracing.com/parts/nal-12371043

Chevrolet Performance 12371043 Chevrolet Performance Timing Chain Sets | Summit Racing

Free Shipping - Chevrolet Performance Timing Chain Sets with qualifying orders of $109. Shop Timing Chain and Gear Sets at Summit Racing.

www.summitracing.com

BEWARE, there's some evidence that certain blocks have the lifter bores sabotaged by counter-boring the upper part to a larger diameter. The roller lifters hemorrhage oil when the cam lobe pushes the lifter up. Check your lifter bores!

If you insist on putting Vortec heads on the TBI block, you'll want to drill one hole in the head gasket surface of each head, to allow coolant bypass on the right block deck. The other head is drilled "just because" someday you might have the engine apart, and swap heads from left to right.

Thank you so much- I was hoping you'd see this. I'll check the lifter bores, for sure.

Do you think IF the lifter bores are "sabotaged" I could get away with using link-bar solid rollers and STD SBC pushrods? It sure would save a ton; I have those parts already, lol.

FWIW The question was posed to Mike Jones (of Jones Racing Cams) some years ago and he basically said it was "a waste of money; if one wanted solid roller performance, then one should purchase a solid roller". That's why I mentioned my tiny camshaft- I'm not going to spin this thing over 4.5-5krpm.


Thanks for your time!

 

[Schurkey]

I will not put solid lifters--roller or flat-tappet--on a hydraulic cam.

I guess other folks do and get by with it. Better to put hydraulic lifters on a solid cam, if you just have to mis-match cams and lifters.

I've heard of two cases of sabotaged lifter bores. Doesn't seem to be common, or at least folks don't notice/talk about it much.

 

[n2xlr8n]

Again- thank you very much for your time; I really appreciate the help.

I'll report back what I find and how it turns out, as well as the correct 5/16ths bolt length.

Edit: The (3) 5/16ths bolts for the spider are 5/8" in length.

 

[Erik the Awful]

Worst case: Let's say the bosses aren't even on this block- can I simply use old school 350 SOLID roller lifters with a tie-bar?

WIW The question was posed to Mike Jones (of Jones Racing Cams) some years ago and he basically said it was "a waste of money; if one wanted solid roller performance, then one should purchase a solid roller". That's why I mentioned my tiny camshaft- I'm not going to spin this thing over 4.5-5krpm.

That answer works for a race motor, not a daily driver. Solid rollers require regular adjustment. You're not looking for solid roller performance, and you shouldn't have to deal with solid roller problems.

 

[n2xlr8n]

That answer works for a race motor, not a daily driver. Solid rollers require regular adjustment. You're not looking for solid roller performance, and you shouldn't have to deal with solid roller problems.

Thanks for your response.

With all respect, in my experience I'm doubtful solid lifters with 125-130 lbs seat pressure and 0.450" lift would require more than a simple check every year or so, unlike a SR camshaft with ~0.700 lift, 240 lbs on the seat and inverted radius / ramp rates out the wazoo, no?

I was more curious as to whether or not they would actually work with longer pushrods, but I'll certainly admit I don't know much about this combination.

Great forum.

 

[n2xlr8n]

Update- the engine was made in September of 88, but it does in fact have tapped bosses (Thank you Jesus).

I won't be doing any experimenting on this one, lol.

Thanks for the help, everyone!

 

[PlayingWithTBI]

Update- the engine was made in September of 88, but it does in fact have tapped bosses (Thank you Jesus).

FWIU, they didn't have the bosses on newer TBI blocks - maybe 94 - 95s? My newer Mr Goodwrench block from ~2000 has them too.